New York Police Commissioner Raymond Kelly on Sunday said there is no evidence to support the claim by a Pakistani Taliban commander that he was behind Saturday's failed car bomb attempt on Times Square.
"Although a Taliban bomb-maker has claimed on the Internet that the car bomb was placed on Times Square to avenge the deaths of mujahideen fighters, we have no evidence to support this claim," Kelly told a press conference, Xinhua reported.
He was referring to a claim made by Pakistani Taliban bomb-maker Qari Hussain Mehsud in an audiotape posted on Youtube.
Kelly also said another claim of responsibility emailed to a local news organisation is being investigated.
The police chief said authorities are examining the video of a "white male in his 40s," who was seen as shedding a dark-colored shirt, revealing a red one underneath.
"He put the dark one into the bag that he was carrying," Kelly said. "This happened about half a block away from where the vehicle was parked."
The individual could be completely innocent, but he did appear to be acting in a "furtive manner", Kelly added.
The police commissioner said detectives are also travelling to a town in the neighbouring state of Pennsylvania, where a tourist believes that he may have captured the suspect's image on his video camera.
Earlier on Sunday afternoon, a bomb squad of the New York Police Department opened up the gun locker found in the back of the vehicle recovered from Times Square.
The locker contained eight bags of "unknown substance" and an inverted metal pipe containing a bird's nest of wires and firecrackers.
Police are working with environmental protection authorities to further identify the bags of material, Kelly said.
He said authorities are combing through hundreds of hours of surveillance video from the Times Square area, which may provide additional information.
The police chief asks members of the public to come forward if they have any information about the incident, including any video or other images of the vehicle or its driver.
At about 6.30 pm on Saturday, a T-shirt peddler alerted local authorities of a suspicious, smoking sports utility vehicle on Times Square, a famous tourist attraction, which prompted an evacuation of visitors. Bomb squad officers later discovered propane gas tanks, fireworks and timing devices in the car.
Times Square reopened to vehicle and pedestrian traffic Sunday, but US Homeland Security Secretary Janet Napolitano said authorities are "alerting state and local law enforcement authorities, and others to stay on their toes".