The plane was carrying 278 passengers
An incident on an airliner arriving in Detroit from the Netherlands was an attempted terrorist attack, a senior administration official told the BBC.
Sources say a man tried to blow up the jet with 278 passengers on board, but was subdued and taken into custody. No-one was seriously hurt.
The suspect said he had been acting on behalf of al-Qaeda, a police source told the Associated Press news agency.
President Barack Obama has ordered increased security for air travel.
We heard a little pop, then a bit of a smoke and then some flames and yelling and screaming and then somebody said the guy was subdued.
White House spokesman Bill Burton said the president was monitoring the situation.
US and Dutch media report that the suspect is a Nigerian national studying in London.
A source described by the Associated Press as a "senior US counter-terror official" said the passenger had been planning to blow up the plane but the device failed.
The official spoke on condition of anonymity because the investigation was continuing, the agency added.
'Taped to his leg'
Northwest Airlines Flight 253 had been arriving from the Dutch capital Amsterdam when the incident occurred at Detroit Metropolitan Airport on Friday afternoon.
According to a report on the ABC television network, the suspect told authorities he had had explosive powder taped to his leg and used a syringe of chemicals to mix with the powder that was to cause explosion.
Another US intelligence official quoted by AP said an explosive device had been used consisting of a "mix of powder and liquid".
The FBI and the Federal Aviation Administration are investigating.
A robot was used to check the plane at one stage.
At least one passenger was taken to the University of Michigan Medical Center in Ann Arbor.
Passengers told AP about a bang and smoke and fire, which some took to be a firecracker going off.
Syed Jafri, a US citizen who had flown from the United Arab Emirates, said the incident occurred during the plane's descent.
He said he was seated three rows behind the passenger and had seen a glow and noticed a smoke smell.
Then, he said, "a young man behind me jumped on him".
"Next thing you know, there was a lot of panic," Mr Jafri added.
Another unnamed passenger heard a "little pop", then saw "a bit of a smoke and then some flames".
After "yelling and screaming", the attacker was subdued. "They took him out and it was really quick," the passenger added.
Another unnamed eyewitness said a man had reacted to the explosion by jumping "over all the other people and he took care of it so the fire went out".
Friday, December 25, 2009
Bombing suspect is a Nigerian national studying in London.
Transatlantic jet incident 'was terror attack bid'