WASHINGTON (AP) - Passengers say an attempted terrorist attack on a Christmas Day flight to Detroit began with a pop and a puff of smoke.
Two law enforcement officials said the man claimed to have been acting on instructions from al-Qaida to detonate the device above U.S. soil and destroy the plane.
The commotion began as Northwest Airlines Flight 253, carrying 278 passengers and 11 crew members from Amsterdam, prepared to land in Detroit.
Travelers said they smelled smoke, saw a glow, and heard what sounded like firecrackers. People on the plane say at least one person climbed over others and jumped on the man.
The White House said it believed it was an attempted act of terrorism and stricter security measures were quickly imposed on airline travel.
Law enforcement officials say they want to figure out exactly how the device, consisting of powder and a liquid, was made and how much of a threat it may be.
In 2006, investigators in London uncovered a plot to use liquid-based explosives to blow up airliners.
The case prompted new restrictions and investigators are trying to determine whether the rules need to be tightened again.
Officials said the man appeared badly burned on his legs, indicating the explosive was strapped there.
The Northwest Airlines flight that was an apparent terrorist target began in Nigeria and went through Amsterdam en route to Detroit.
Schiphol airport in Amsterdam is one of Europe's busiest, and a main transit point for passengers traveling from Africa and Asia to North America.
It strictly enforces European security regulations including only allowing small amounts in hand luggage that must be placed inside clear plastic bags.
But security at Nigeria's two major international airports in the capital Abuja and in its megacity Lagos are more of a concern.
Federal officers often focus their time on keeping hagglers and taxi drivers out.
Bags quickly pass through X-ray scanners, and those who are watching incoming passengers do not typically conduct tests for explosive residue on carry-on baggage or on shoes.
But a spokesman for Nigeria's airports authority says all passengers and their luggage are screened before international flights.
He says the procedures received a passing mark after an audit by the U.S. Transportation Security Administration.