ISLAMABAD - Pakistan's Taleban chief promised attacks on major United States cities in a video apparently dated early April and released after the failed car bomb attempt in New York City, a monitoring group said.

It followed reports of another video in which the group apparently tried to take credit for that attempted strike.

US authorities have played down the potential connection between the Pakistani militant network and the car bomb attempt in Times Square, saying there is no evidence of such a link and the group does not have the global infrastructure to carry out such a strike.

Investigators were keeping an open mind on whether the motive was rooted abroad or linked to a domestic cause in the US. However, the Pakistani Taleban are allied with al Qaeda, which could expand their reach.

The latest video is about nine minutes long and features Hakimullah Mehsud, the Pakistani Taleban chief, according to IntelCentre, a US-based group that monitors militant media.

Mehsud does not specifically mention New York, but says he is speaking on April 4 of this year, and promises that, "God willing, very soon in some days or a month's time, the Muslim [community] will see the fruits of most successful attacks of our fedayeen in USA".

Fedayeen usually refers to suicide bombers, which the car bomb attempt in New York did not involve.

Mehsud also refutes earlier Pakistani and American claims that he died in a US missile strike in January, a belief Pakistani intelligence officials recently revised.

The video follows a second, shorter clip in which the group appears to claim responsibility for the attempted car bomb, according to the SITE Intelligence Group, another monitoring organisation.

In the one minute 11 second video, allegedly released by the Pakistani Taleban, the militant group says the attack is revenge for the death of its leader, Baitullah Mehsud, and the recent slaying of al Qaeda in Iraq leaders Abu Omar al-Baghdadi and Abu Ayyub al-Masri, who were killed by US and Iraqi troops last month north of Baghdad.

SITE, a US-based terrorist tracking organisation, first uncovered the video on YouTube. The tape, which later appeared to have been removed from the website, makes no specific reference to the attack in New York, nor does it mention the location or that it was a car bomb.

In a copy of the tape provided by SITE, an unidentified voice speaking in Urdu, the primary language in Pakistan, says the group takes "full responsibility for the recent attack in the USA".

New York City's police commissioner said there was no evidence of a Taleban link to the failed car bomb.

Mayor Michael Bloomberg noted that the investigation was in its early stages but said, "So far, there is no evidence that any of this has anything to do with one of the recognised terrorist organisations".

The Washington Post said terrorism experts were sceptical that the Taleban could have organised the attack to avenge deaths that occurred less than two weeks ago.

The claim could not be immediately verified. But if it turns out to be genuine, it would be the first time the Pakistani Taleban has struck outside South Asia.

It has no known global infrastructure like al Qaeda. In at least one past instance, the Pakistani Taleban has claimed responsibility for an attack it played no role in.

Last year, the Pakistan Taleban's then commander, Baitullah Mehsud, vowed to "amaze everyone in the world" with an attack on Washington or even the White House. But Mehsud also, reportedly, said his men were behind a mass shooting at the American Civic Association in Binghamton in April 2009. That was false.

The Times Square attack "lends itself to the idea that this was a low-capability group or even a lone individual", Henry Wilkinson, senior intelligence analyst at London-based security company Janusian said.

Police investigating the attack - that could have set off a deadly fireball in the major tourist destination - focused on finding a man who was videotaped shedding his shirt near the 4WD where the bomb was found.

Police said yesterday that the petrol-and-propane bomb was crude but could have sprayed shrapnel and metal parts with enough force to kill pedestrians and knock out windows on one of America's busiest streets.

The surveillance video shows an unidentified white man, apparently in his 40s, slipping down an alley and taking off a shirt, revealing another underneath.

In the same clip, he's seen looking back in the direction of the smoking vehicle and furtively putting the first shirt in a bag, Kelly said.

Authorities don't know how deadly the bomb could have been, how it failed or who was responsible.

Police had already identified the registered owner of the 1993 Nissan Pathfinder - which didn't have an easily visible vehicle identification number and had licence plates from another car - and were looking to interview him.

Police were searching more video, believed to be in the possession of a Pennsylvania tourist, of a person spotted near the car.

- AP