New York police are trawling through hundreds of hours of video tape from surveillance cameras in the hunt for those responsible for the attempted bombing in Times Square.

Police say they have numerous leads already but none of them point to the work of international terrorists, despite a claim of responsibility from the Pakistani Taliban.

Propane tanks, fireworks, petrol and a clock device were all removed from the vehicle parked in Times Square, and police say the “amateurish” bomb could have created a “significant fireball” if it had detonated.

Theatre-goers were heading to dinner while thousands of other tourists filled Times Square when street vendors near 45th Street spotted the car.

Rallis Gialaboukis was selling hot dogs about seven metres away.

“[The car was] abandoned, hazard [lights] on and people started talking amongst us,” he said.

“[We could] see the smoke coming out of the car, like seeping through the windows, and you could see it.

“You couldn’t see what’s in the car, nobody could see and then as they were trying to evacuate … away from it it just went off inside the car – an explosion went off inside the car.”

Police Commissioner Ray Kelly said the bomb was probably beginning to detonate but malfunctioned.

“It looks like it would have caused a significant fireball and you have large numbers of pedestrians in that area so yep, we were lucky that it didn’t detonate,” he said.

The police have 82 of their own surveillance cameras to check, plus hundreds of hours of material from privately owned security cameras in the area.

Already they are looking for a white man in his 40s who was acting suspiciously.

“He also was seen shedding a dark-coloured shirt, revealing a red one underneath. He put the darker one into a bag that he was carrying,” Commissioner Kelly said.

“This happened about a half block from where the vehicle was parked.”

Detectives are also en route to a town in Pennsylvania where a tourist believes he may have captured the suspect’s image on his video camera.

Taliban claim

The Pakistani Taliban have claimed credit in a video message but Commissioner Kelly says nothing indicates they are to blame.

Homeland security secretary Janet Napolitano said authorities were treating the incident “as if it could be a potential terrorist attack”.

“The derivation of that, we do not know. And that’s what the investigation will tell us,” she said.

New York congressman Peter King says the possible connection to international terrorist groups cannot be ruled out.

“Just because it’s not done by a bombing expert doesn’t mean that we can rule out an international connection or even just having a cell or operatives in this country working together,” he said.

Twenty-four hours after the attempted bombing, Times Square was again filled with people.

But New York’s mayor Michael Bloomberg says the attempted bombing is another reminder of what the city faces every day.

“Tonight is a further reminder of the dangers that we face,” he said.

President Barack Obama, who is surveying a massive oil slick in Louisiana, says he is monitoring the situation in New York and will ensure justice is done.