Investigators are poring over a wealth of evidence to find out who tried to detonate a car bomb in Times Square - New York's bustling entertainment area.
The bomb, described as "amateurish", consisted of propane tanks, fireworks, petrol and a clock device. It was planted in a sports utility vehicle.
NYC police commissioner Ray Kelly said there was no evidence to support a Taliban link to the bomb attempt.
It followed a claim by the Pakistani Taliban early on Sunday.
In a video message purportedly released by the Pakistani Taliban, the militants said it was a revenge attack for the deaths of its leader and the leader of al-Qaeda in Iraq.
At a news conference on Sunday, Mr Kelly said the device in the Nissan Pathfinder consisted of two clocks connected by wires to a can, which they believed was the detonator, propane tanks and a gun locker.
Mr Kelly also said a white man in his 40s was seen removing a dark shirt in the area and putting it in a bag.
The commissioner added that police would shortly speak to a person in Pennsylvania who believed he may have recorded the man on a video camera.
Experts still had a huge amount of camera footage to pore over, Mr Kelly said.
"It's not easy to go through these tapes. I think we had 82 cameras in the area - we've looked at 30 of those cameras. Three of them had some value," he said.
Earlier on Sunday, US Homeland Security Chief Janet Napolitano said so far there was no evidence that it was more than a "one-off event".
But she added that it was regarded as "a potential terrorist attack".
BBC