Ann Romney's airplane made an emergency landing in Denver, Colo., on Friday after its cabin filled with smoke, the campaign of her husband, Republican presidential challenger Mitt Romney, said.

Everyone on board the private plane was safe, a campaign spokesman said.

The Federal Aviation Administration said the Canadair Challenger 601 operated by World Wide Jet was traveling from Omaha, Neb., to Santa Monica, Calif., and was diverted to Denver at about 2:40 p.m. (4:40 p.m. ET) after the pilot reported smoke in the cockpit. Upon landing, passengers exited via the stairs on the taxiway, the FAA said.

Anne Romney and her husband spoke shortly after the landing, Romney campaign press aide Rick Gurka told reporters traveling with the candidate in Las Vegas.

The cause was believed to be an electrical fire, Romney campaign press secretary Andrea Saul said in a tweet.

Reuters contributed to this report.

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