ROMULUS, Michigan (AP):

An attempted terrorist attack on a Christmas Day flight began with a pop and a puff of smoke - sending passengers scrambling to subdue a Nigerian man who claimed to be acting on orders from al-Qaida to blow up the airliner, officials and travellers said.

The commotion began as Northwest Airlines Flight 253, carrying 278 passengers and 11 crew members from Amsterdam, prepared to land in Detroit just before noon on Friday.

Travellers said they smelled smoke, saw a glow, and heard what sounded like firecrackers. At least one person climbed over others and jumped on the man, who officials say was trying to ignite an explosive device.

"It sounded like a firecracker in a pillowcase," said Peter Smith, a passenger from The Netherlands. "First there was a pop, and then (there) was smoke."

Smith said one passenger, sitting opposite the man, climbed over passengers, went across the aisle and tried to restrain the man. The heroic passenger appeared to have been burned.

Afterwards, the suspect was taken to a front-row seat with his pants cut off and his legs burned.

Badly burned

Multiple law-enforcement officials also said the man appeared badly burned on his legs, indicating the explosive was strapped there.

The components were apparently mixed in-flight and included a powdery substance, multiple law enforcement and counterterrorism officials said.

The White House said it believed it was an attempted act of terrorism and stricter security measures were quickly imposed on airline travel.

Dutch anti-terrorism authorities said the US has asked all airlines to take extra precautions on flights worldwide that are bound for the United States.

The incident was reminiscent of Richard Reid, who tried to destroy a transatlantic flight in 2001 with explosives hidden in his shoes, but was subdued by other passengers.

Multiple law-enforcement officials identified the suspect in Friday's attempted attack as Umar Farouk Abdul Mutallab. He was described as Nigerian.

One law-enforcement official said the man claimed to have been instructed by al-Qaida to detonate the plane over US soil, but other law enforcement officials cautioned that such claims could not be verified immediately, and said the man may have been acting independently - inspired, but not specifically trained or ordered by terror groups.

Investigations

All the officials spoke on condition of anonymity because the investigation was continuing.

Intelligence and anti-terrorism officials in Yemen said they were investigating claims by the suspect that he picked up the explosive device and instructions on how to use it in that country. The officials spoke on condition of anonymity because they are not authorised to speak to the media.

An intelligence official said he was being held and treated in an Ann Arbor, Michigan, hospital. The hospital said one passenger from the flight was taken to the University of Michigan Medical Centre in Ann Arbor, but referred all inquiries to the FBI.