At MSNBC:

A half hour before landing, an air marshal smelled smoke and confronted a man emerging from a bathroom who claimed he was trying to set his shoes on fire, WNBC reported.

It was uncertain if anything actually was on fire or if this was a joke, NBC reported. Investigators were looking to see what might be in the man’s shoes.

Sources told NBC News that the passenger who was subdued was a Qatari diplomat who would have full diplomatic immunity.

After the pilot declared an emergency, military jets scrambled and escorted the jet into Denver, where the plane remains in a secure area, NBC affiliate WRC reported.