U. S. officials said on Thursday that a Qatari diplomat who sparked a security alert after he lit a pipe in a United Airlines in-flight bathroom will not be charged.

U. S. State Department spokesman P. J. Crowley said that however Mohamed al-Madadi, 27, the third secretary of the Qatari Embassy in Washington, will be sent home to Qatar.

Under international protocol, diplomats enjoy broad immunity from prosecution in foreign countries.

The official Qatar News Agency has reported that Qatari Ambassador Ali bin Fahad al-Hajri called Wednesday's incident, which prompted security officials to scramble two F-16 fighter jets to intercept the Boeing 757 and escort it to Denver International Airport, "a mistake" and said Madadi was traveling on diplomatic business.

He was making a consular visit to convicted al-Qaida agent Ali al-Marri, a citizen of Qatar, who has been imprisoned since 2001, the New York Times has reported.

The 157 passengers and six crew members on Flight 663 were never in danger, U. S. aviation security officials have said.

Britain's Daily Telegraph also reported that Madadi had been in the lavatory a long time, and when questioned about smoke emerging through the door, he claimed diplomatic immunity and made a sarcastic comment he intended to set fire to his shoe.

The Madadi incident came a week after U. S. President Barack Obama unveiled new security measures subjecting all inbound passengers to screening methods that use "real-time intelligence" to target potential threats. (With Inputs from Agencies)