An air marshal smelled smoke and confronted a man emerging from a bathroom who claimed he was trying to set his shoes on fire a half hour before landing, according to reports. The marshal subdued the man and the pilot alerted authorities including FBI.

It was not known if anything actually was on fire or if this was simply a joke.

United Flight 663 landed safely at Denver International Airport, airline and airport officials said. It was a Boeing 757 with 157 passengers and six crew members aboard,offcials said.

The latest incident comes a week after U.S.President Barak Obama announced new security measures to replace the mandatory screening of air travelers from 14 countries, which the U.S government alleged were linked with terrorist activities.