Secretary of State John Kerry said a North Korean missile launch would be a “huge mistake" and reiterated that the United States would defend its allies if necessary after arriving in the South Korean capital on Friday.

Kerry also warned Pyongyang that firing a medium-range missile would be a "provocative and unwanted act."

“Kim Jong Un needs to understand, as I think he probably does, what the outcome of a conflict would be,” Kerry said. “Our hope is we can get back to talks."

“The rhetoric that we are hearing from North Korea is simply unacceptable by any standard,” Kerry added. The United States “will, if needed, defend our allies and defend ourselves,” he said.

North Korea's two medium-range missiles remained fueled and ready to fire on the country's east coast Friday, U.S. military and intelligence officials said. However, there had been no heightened movement or activity by the country's military that would suggest an imminent rocket launch.

Kerry met with South Korean President Park Geun-hye on Friday for the first of four days of talks amid speculation about North Korea’s military capabilities and uncertainty over what threat the isolated nation’s erratic leader may make next.

The South Korean president thanked Kerry for his leadership in recent weeks as North Korea has escalated its rhetoric.

“I also wish to express my appreciation for your leadership in having the recent G8 foreign ministers meeting in London issue a stern warning to North Korea,” Park told Kerry through an interpreter. “I also wish to say given the escalating tensions on the peninsula, your visit will certainly showcase how closely we are coordinating our efforts.”

John Everard, a former British ambassador to North Korea, said Pyongyang was going to have to make a decision whether to fire or not fire their missiles soon.

“They are liquid-fueled missiles, and the liquid that you use for such missiles is quite nasty stuff,” he said. “You can't leave the missile full of fuel because the fuel will corrode the missile.  You either have to fire it within about 10 days of fueling it or you have to defuel it, which is a messy and dangerous process. So they're coming to a crunch point.”

“I suspect that they are planning on launching.  I don't think -- or I hope -- that the missile won't be directed at anything. I think they will probably go for a test, drop the missile into the sea," he said. "And we hope that if they do that, they don't feel the need to fly it over the top of Japan, which they did in 1998.”

Everard added that “frankly their missiles are not that good, they are old-fashioned …  [and] their guidance systems are poor.”

Later on Friday, South Korea and the U.S. released the following joint statement:

The 60-year alliance between the United States and the Republic of Korea is crucial for security and stability in the Asia-Pacific region. The United States reaffirms its commitment to the defense of the Republic of Korea in the wake of recent unacceptable provocations by North Korea.

Both sides agree on the importance of the denuclearization of North Korea, knowing that North Korea's dangerous nuclear and missile programs threaten not only its neighbors, but also its own people.

The United States stands vigilantly by the Republic of Korea's side, and is prepared for and capable of defending and protecting itself and its allies. Both of our countries are taking prudent measures - both military and diplomatic - to enhance our security. At the same time, the two countries remain committed to the goal of peaceful denuclearization. In this context, the United States welcomes the Trust-building Process on the Korean Peninsula proposed by President Park Geun-hye.

We will continue working with all Six-Party partners and the international community to make clear that North Korea must adhere to its international obligations and commitments or face further isolation. We will continue to encourage North Korea to make the right choice. If North Korea does so, we are prepared to implement the commitments under the 2005 Six-Party Joint Statement. But Pyongyang must prove its seriousness by taking meaningful steps to abide by its international obligations. 

Nuclear missile capability?
Kerry addressed a report by the Pentagon’s Defense Intelligence Agency, which was disclosed in a congressional hearing on Thursday, that said the agency has “moderate confidence” that North Korea is capable of mounting a nuclear weapon on a missile, but that such a weapon would likely not be reliable.

After the hearing, Pentagon spokesman George Little said “it would be inaccurate to suggest that the North Korean regime has fully tested, developed or demonstrated the kinds of nuclear capabilities referenced” at the Thursday hearing.

Kerry said Friday that while North Korea has tested a nuclear device, they have not yet shown the capability to build a weapon small enough to be mounted on a ballistic missile.

“It is inaccurate to suggest that the DPRK [Democratic People's Republic of Korea -- North Korea's official name] has fully tested, developed, and demonstrated capabilities that are articulated in that report,” Kerry said. “But obviously they have conducted a nuclear test so there is some kind of device. But that is very different from miniaturization and delivery and from tested delivery and other things. Does it get you closer to a line that is more dangerous? Yes.”

Kerry said the United States would continue to work with allies including Japan to find other ways to de-escalate tensions, and said that President Barack Obama has ordered a number of unspecified exercises not to take place to help calm the heated rhetoric.

"We are all united in the fact that North Korea will not be accepted as a nuclear power," Kerry added.

Kerry also planned to visit China and Japan on his East Asia trip. The U.S. has engaged in aggressive diplomacy with China, North Korea’s northern neighbor and benefactor, in the latest round of saber-rattling.

Pyongyang relies on China for basic supplies like food and fuel, as well as a diplomatic link to the world, but Beijing’s good will toward the impoverished nation has recently waned. There are signs Chinese officials have tired of the North’s bellicose rhetoric, and China supported a round of United Nations sanctions following the country’s third nuclear test.

“We do not want to see chaos and conflict on China’s doorstep,” Chinese Foreign Ministry spokesman Hong Lei told NBC News.

NBC News' Jim Miklaszewski and Ian Johnston, Reuters and The Associated Press contributed to this report.

Slideshow: North Korea's young leader, Kim Jong Un

The youngest son of Kim Jong Il succeeded his late father in 2011, becoming the third member of his family to rule the unpredictable and reclusive communist state.

Launch slideshow

Related:

Check out our Google+ Hangout on North Korea

Analysis: China grows weary of North Korea

Full North Korea coverage from NBC News

This story was originally published on Fri Apr 12, 2013 4:07 AM EDT

News analysis

Updated at 5:41 a.m. ET on Nov. 7: Barack Obama faces no shortage of foreign challenges as he enters his second term as commander in chief.

While it is impossible to predict what may come, here’s a look at 10 issues likely to emerge as priorities for his administration:

1. Possible Afghan collapse/civil war
The Afghan government has been propped up by American and NATO troops and money but has failed in its basic functions of establishing national trust, security and unity. Afghanistan could devolve into a civil war as U.S. troops draw down in 2014, with old rivalries re-emerging between the north and south/southeast.

Once again, the country could be torn by an ethnic war between the Pashtuns and the now-defunct Northern Alliance, a legion of Tajik, Uzbek and Hazara militias. The risk is that Afghan security forces will then split along ethnic lines and President Hamid Karzai, whom critics accuse of being an uncooperative U.S. ally, could become an even greater liability.

On a recent visit to Afghanistan I spoke to some Tajik villagers outside Kabul, who promised me they would start fighting once American troops leave. They said they would battle a group of pro-Taliban Pashtun villagers nearby. When asked if Karzai's troops would be able to stop a clash, one tribal elder told me, "The corrupt government in Kabul? It can't do anything."

The dangers of an Afghan collapse are many: Afghan deaths, a loss of American prestige, a loss of NATO prestige, a moral blow to U.S. troops and veterans, a Taliban resurgence, huge setbacks for women, and greater power for Pakistan and Pakistani extremists.

Read more Afghanistan coverage from NBCNews.com

Slideshow: Afghanistan: Nation at a crossroads

Aref Karimi / AFP - Getty Images

More than ten years after the beginning of the war, Afghanistan faces external pressure to reform as well as ongoing internal conflicts.

Launch slideshow

2. Possible Iran implosion or explosion
Iran, which is being pushed to a breaking point by U.S.-led currency and banking sanctions, won't simply sit back and watch its economy crumble. Persia is 7,000 years old and will fight to survive.

The increasingly isolated country is likely to act in one of three ways: accommodation and negotiation, weaponization, or diversion.

Faced with the crippling sanctions, Iran could simply decide it is paying too high a cost to pursue its nuclear program and could opt for negotiations and reconciliation with the United States and other members of the international community. This is clearly the preferred option of American leaders.

The other possibilities are more problematic. Iran could rush toward a nuclear capability, deciding the best way to survive is to obtain weapons so horrific that no one would dare attack. A nuclear program has arguably worked as a deterrent for North Korea and other states -- would Moammar Gadhafi have been deposed and summarily killed if Libya had had nuclear weapons? Iranians might not think so.

Source: Back-channel talks but no US-Iran deal on one-to-one nuclear meeting

A less risky approach would be to provoke a diversionary conflict through Hamas in Gaza, Hezbollah in Lebanon, the Houthis in Yemen, the Shiites in Bahrain, the Kurdistan Workers Party in Syria and Turkey, its position in the Strait of Hormuz -- or it could try to inflame anti-American and anti-Israeli sentiment.

Iran also could try to attack the American economy through sabotage or cyber warfare. Cornered as it is, Iran could become the aggressor instead of -- as it sees itself -- the passive victim.

Slideshow: Everyday life in Iran

At schools, in shops, and on the streets of big cities and small towns, daily life plays out in Iran.

Launch slideshow

How Iran acts is up to its choosing but it's hard to see how it won't act -- for better or worse -- as the sanctions continue to bite.

Read more Iran coverage from NBCNews.com

3. Rise of the Muslim Brotherhood
The Arab Spring has empowered the Muslim Brotherhood across the Middle East and beyond. It and other ideologically similar and allied groups run the governments of Egypt, Tunisia and Gaza.

In Syria, the Brotherhood has a strong presence among the rebels and in Yemen, it runs half the government and much of the state's day-to-day functions. In Jordan and Morocco, the Brotherhood is the main opposition to the countries' ruling royal families. In leaderless Libya, it is an increasingly organized voice. And in Algeria, the movement's officials warn that their revolution is coming.

The Muslim Brotherhood's influence in the Middle East is likely to evolve in one of two ways. Military regimes that have been pushed aside could fight back and launch counter-Islamic revolutions, clawing back the Brotherhood's gains and keeping it tied up in internal political battles. This is already starting to happen in Egypt.

Analysis: Egypt's big turn under the Muslim Brotherhood

Conversely, the Muslim Brotherhood could consolidate its gains and dominate electoral politics in the Middle East for the next several years.

For the United States, the rise of the Brotherhood is not in itself a major challenge. Most of its leaders say they want good relations and economic ties with Washington. The problem, however, is Israel. The Brotherhood is fundamentally anti-Israel, and Washington is fundamentally pro-Israel.

While analysts can debate which presidential candidate is closer to Israel, both have expressed their commitment to it and its security -- just as every U.S. president has done.

But the Muslim Brotherhood will not make the same commitments to Israel's integrity and security. While campaigning to win the election in Egypt, the Brotherhood held rallies featuring speakers who called for the restoration of the Islamic Caliphate with Jerusalem as its capital.

The Brotherhood does not understand why Washington chooses to befriend one small country at the expense of relations with millions of Arabs and over a billion Muslims. Washington rejects having to make this choice.

This rift could become a showdown and devolve into violence. The timing depends on American policy and outside provocations that can be either by design -- "peace" flotillas to Gaza, Hamas rockets, an Israeli assault on Gaza -- or by accident, such as bigoted and dumb Internet movies.

4. Cyber threat
The United States has spent a decade fighting terrorists with some notable and many debatable successes. But bombs aren't the only kind of threat. In fact, a successful cyber attack could cause national and international chaos far exceeding a bombing in a major U.S. city.

Defense Secretary Leon Panetta recently warned about a possible cyber Pearl Harbor. Many military officials and analysts I know fully agree with him.

Panetta: Cyber intruders have already infiltrated US systems

5. Israeli strike on Iran
Israel may attack Iran's nuclear program if it believes sanctions are failing. The strike would likely delay but not stop the program, experts say. For the time being, Israel has decided to wait and see what impact the international sanctions have.

If Iran chooses a quick rush to make a bomb, Israel will most likely change course and opt for a military solution. Prime Minister Benjamin Netanyahu made that point abundantly clear when he drew a red line at the United Nations and held up a picture of a bomb.

Read more Israel coverage from NBCNews.com

6. Revival of al-Qaida/Ansar al-Sharia
Al-Qaida's leaders have been killed and hunted, but the group hasn't gone away. Many al-Qaida factions have re-branded themselves under a new name: Ansar al-Sharia (partisans of Islamic law). Some of the militants also are finding new comfortable homes in the post-Arab Spring Middle East, blending into Salafist (Sunni fundamentalist) movements.

7. Rift with Pakistan
Pakistan and the United States have been locked in an uncomfortable marriage since the Sept. 11, 2001, attacks on the United States, and arguably long before that.

US, Pakistan should 'divorce,' ex-ambassador to Washington says

Critics accuse Pakistan of taking American counter-terrorism money and military support, while at the same time supporting terrorist groups.

Slideshow: Pakistan: A nation in turmoil

Muhammed Muheisen / AP

Images of daily life, political pursuits, religious rites and deadly violence.

Launch slideshow

If the United States cuts off Pakistan -- which may happen as Washington becomes less reliant on Pakistani supply routes into Afghanistan -- Islamabad could become more belligerent, which would cause relations to deteriorate further. The withdrawal from Afghanistan will change the costly status quo that has existed with Pakistan since 9/11, and that change is unlikely to go smoothly.

Read more Pakistan coverage from NBCNews.com

8. Mexico and the growing war on drugs
According to some estimates, Mexico has become the most dangerous country in the world. Around 50,000 people have been killed in the country's drug wars. It is unclear if Mexico's President-elect Enrique Peña Nieto will be able to contain the violence, which has spread south to Central America and is showing signs of leaking north into the United States.

Read more Mexico coverage from NBCNews.com

Slideshow: Narco culture permeates Mexico, leaks across border

Mexico's drug war is also part of a drug culture with roots in music, movies and even religion

Launch slideshow

9. US 'pivot' to Asia/China slowdown
In 2011, China overtook Japan to become the world's second-largest economy after the United States. The Obama administration has acknowledged China's growing military and political power, and has pledged to "pivot" or deploy more than half of the U.S.' naval assets to the Asia-Pacific region by the end of the decade. This, some argue, has contributed to souring relations between the two powers.

Adding to the troubles, China isn't cheap anymore and Chinese workers are no longer as willing to accept poor conditions and little pay. Strikes are increasingly common. Removing dissent from Chinese Internet sites is a full-time job for government censors. Growth rates remain high, but the cost of living and labor demands are going up.

Factories are already moving out of China to cheaper labor markets in Indonesia and Bangladesh. If China's economic growth slows for a prolonged period, the world will be dramatically impacted. The country's economic expansion has driven up oil prices and has made parts of the Middle East, Russia and Brazil exceptionally rich. Could labor unrest threaten the ruling Communist Party's grip? Any move from this giant creates a huge wake that will quickly wash onto American shores.

Read more China coverage on NBC's Behind The Wall

10. United States: Drifting?
For a decade, the United States has made fighting terrorism its main foreign policy goal. This is by definition a reactionary policy and is limited in focus -- without a global vision or sense of destiny.

In contrast, American rivals appear to have grand plans in place. Russia, under President Vladimir Putin, seems intent on regaining its Soviet and Tsarist glory. Turkey is flexing its muscles regionally and is re-establishing some of its Ottoman legacy and prominence. China is looking to consolidate its hold on swathes of Asia and beyond.

Full coverage: NBCNews.com's The World is Watching series

But what does the United States want to do? What is our goal? It is impossible to be influential if we don't know where we are going -- and any malaise would be damaging to the national interest. World powers must move to survive. Drifting is sinking.

More election coverage from NBCNews.com:

• Victorious Obama 'more determined' in face of challenges
• Now that he's won, six splitting headaches waiting for Obama
• Democrats retain control of Senate with series of hard-fought wins
• One big winner in Tuesday's vote: health reform
• Romney's English cousin sad he lost, sort of
• Rape remarks sink two Republican Senate hopefuls
• In costliest-ever Senate race, Warren beats Brown for Mass. seat
• Maine's Harley-riding King vowed to 'shake up' D.C.
• Republicans easily maintain control of House
• Colorado, Washington approve recreational marijuana use
• Wisconsin's Baldwin becomes 1st openly gay senator
• Pence in as governor of Indiana; Hassan wins in N.H.
• World welcomes Obama's 2nd term - but many challenges loom
• Majority of voters see American on wrong track
• Top 10 foreign policy issues facing Obama

Follow NBC Politics on Twitter and Facebook

LOS CABOS, Mexico -- President Barack Obama expressed support for his European counterparts and their measures to manage the fiscal crisis as the G20 Summit in Los Cabos, Mexico wrapped up Tuesday, saying he believes they are "ready to do what is necessary to hold the Eurozone together."

Behind the scenes, however, one senior administration official said the focus of the summit was to convince German Chancellor Angela Merkel to pull away from an austerity plan and focus more on spending and creating jobs.

/

President Barack Obama, German Chancellor Angela Merkel and Chinese President Hu Jintao chat after arriving for the family photo of the G20 summit, at the convention center in Los Cabos, Mexico.

Another senior administration official was asked whether leaders "ganged up" on Merkel; that official replied, "I don’t think I’d describe it that way." But another official said world leaders were very blunt in their efforts to convince Merkel to sign on to the plan.

While the official declaration out of the G20 Summit pointed to a more integrated financial system and an agreement to help Greece stay in the Eurozone, an official says the group was closer to an agreement to create a fund to loan money to troubled countries.

There is no agreement, however, on how such an account would be funded.

Obama said he was "confident" that over the next several weeks, "Europe will paint a picture of where we need to go," but he acknowledged that the world's economy could affect his election prospects. He used the moment to admonish Congress for not acting on the jobs plan he announced last year.

Obama also used his time in Mexico to meet with President Vladimir Putin of Russia and President Hu Jintao of China, where the primary topic of discussion was the unraveling situation in Syria.

While Obama did say he believed both countries understood that civil war was in nobody's interest, it was clear that neither the Russian or Chinese leaders were willing to call for Syrian President Bashar al Assad to step down.

"I wouldn't suggest that at this point, the United States and the rest of the international community are aligned with Russia and China in their positions," the president said carefully.

The president also said he hopes there will be a formal political transition plan in place in Syria in coming weeks, but he was not sure whether Russia or China would sign on. One senior administration official said there was a glimmer of hope that Putin is now willing to consider scenarios where Assad is not in power.

Susan Walsh / AP

President Barack Obama speaks at Hankuk University in Seoul, South Korea, March 26. Obama discussed his Prague agenda to stop the spread of nuclear weapons and seek the peace and security of a world without them.

Updated 12:35 a.m. ET: SEOUL – President Barack Obama’s speech at a university that prides itself on diversity and “producing numerous CEO’s and outstanding diplomats” was billed as an update to his comprehensive nuclear energy and nuclear security agenda he set forth in Prague in 2009.

However, even with strong words directed towards North Korea, his commitment to as one White House source put it, “reduce America's nuclear weapons and the role they play in our national security strategy” could prove to be fodder for his Republican rivals back in the states. 

The president said he believes the United States has a “moral obligation” to act and lead the world in reducing nuclear stockpiles.  He continued, “I say this as president of the only nation ever to use nuclear weapons.  I say it as a Commander-in-Chief who knows that our nuclear codes are never far from my side.  Most of all, I say it as a father, who wants my two young daughters to grow up in a world where everything they know and love can’t be instantly wiped out.”

He announced that when he meets with Russian President-elect Vladimir Putin in May he plans on discussing taking steps so that both Russia and the United States reduce, “not only our strategic nuclear warheads, but also tactical weapons and warheads in reserve.”  The president said such a step would have never been taken before.  It is also a step that is sure to be pounced upon by rivals who already see the reductions he is calling for in defense spending as a sign of weakness.

The president also boasted about steps taken in the last few years to “reduce the number and role of nuclear weapons in our national security strategy” and derided the Cold War stockpiles as being ill-suited for combating the type of terrorism America faces.

But while pushing a message that the United States has to lead the world on reducing nuclear weapons and materials throughout the world, he took time to speak directly to Pyongyang about the choice the North Korean leaders have if they continue to provoke South Korea and the rest of the world.

Obama: North Korean rocket test would isolate regime

Echoing his comments from a press conference yesterday he said, “your provocations and pursuit of nuclear weapons have not achieved the security you seek; they have undermined it. Instead of the dignity you desire, you're more isolated.”

He continued, “There will be no rewards for provocations.  Those days are over.  To the leaders of Pyongyang I say, this is the choice before you.  This is the decision that you must make.  Today we say, Pyongyang, have the courage to pursue peace and give a better life to the people of North Korea.”

The reports that North Korea has moved a long-range rocket to a launch pad this weekend, that could be used to carry a nuclear weapon is just the latest provocation that strained new talks between the US and North Korea.

And once again the president seemed to call for the North Koreans to call for a different way of life:

“This much is true:  The currents of history cannot be held back forever.  The deep longing for freedom and dignity will not go away.  So, too, on this divided peninsula.  The day all Koreans yearn for will not come easily or without great sacrifice.  But make no mistake, it will come.”

Obama calls Korean DMZ 'Freedom's frontier'

The speech at Hankuk University comes right before President Obama is scheduled to meet with the leaders of Russia and China where the thorny issues of North Korea, Syria and Iran are expected to be discussed.  Later in the day he will attend the beginning of the international Nuclear Security Summit. The summit includes 53 countries and four international organizations that have pledged a commitment to securing nuclear materials around the world.

More from msnbc.com and NBC News:

• Wife of Staff Sgt. Bales: 'I just don't think he was involved'
• Scientists: Venice sinking five times faster than thought
• Gunman in Afghan army uniform kills 2 NATO troops
• Cash-for-access scandal leaves UK government reeling
• Retired Turkish general faces terrorism trial
• Transgender candidate booted from Miss Universe Canada

Follow us on Twitter: @msnbc_world