A Qatari diplomat who sparked a bomb scare aboard a United Airlines flight Wednesday will not face criminal charges.

A flight attendant alerted air marshals of smoke coming from a restroom on the Denver-bound flight. Officers subdued the man when he emerged.

Senior law enforcement officials say no explosives were found and that the diplomat had been sneaking a smoke in the bathroom.

"This diplomat was traveling to Denver on official embassy business on my instructions, and he was certainly not engaged in any threatening activity," Qatar's U.S. ambassador, Ali Bin Fahad Al-Hajri, said in a statement on his Washington embassy's Web site. "The facts will reveal that this was a mistake."

An Arab diplomat briefed on the matter identified the diplomat as Mohammed Al-Madadi.

The Transportation Security Administration issued a statement late Wedesday saying the passenger who caused the disturbance is still being interviewed by law enforcement officials.

"All steps are being taken to ensure the safety of the traveling public," the statement read.