Hunt for bomber who targeted the heart of New York

The most audacious terrorist attack on New York since September 11th may have been foiled by "amateurish" bomb-making equipment and a quick-witted t-shirt salesman who alerted police to a car which had been filled with explosives and parked a couple blocks from Times Square, the city's busiest tourist district, on Saturday night.

Police are still trying to establish whether the bomb plot was the work of an isolated extremist or domestic militia, or whether it instead represented an attempt by Islamic terrorists to bring fear back to the streets of the city where al-Qa'ida destroyed the World Trade Center just under a decade ago.

A group calling itself the Pakistani Taliban group released a video last night claiming responsibility for the potentially-devastating but ultimately failed attack, which saw a Nissan SUV packed with propane tanks, petrol, and fireworks, and left a few blocks north of the always-bustling square.

Though smoke began pouring out of the vehicle at around 6.30pm, the bomb failed to detonate, and security teams successfully disarmed it after clearing tens of thousands of tourists and revellers from the surrounding streets. In a tape released on a militant website, the Taliban group nonetheless hailed: "a jaw-breaking blow to Satan's USA."

The car bomb, which security experts say was strong enough to have destroyed the front of nearby buildings if it had gone off properly, was a response to US drone attacks on Pakistan, according to the tape, together with "American interference in Muslim countries" like Afghanistan and Iraq.

However the group's claim was being treated with scepticism by New York's police, who cautioned reporters that Pakistan's Taliban has never previously struck outside of the subcontinent, and boasts a long history of wrongly claiming responsibility for attacks that other terrorist groups have carried out.

There is "no evidence" to support their claim of responsibility," Police Commissioner Ray Kelly told a press conference, adding that "we can't rule anything in or out at this time," and saying that he has no idea whether the attack was planned by a domestic or foreign organisation.

Another theory doing the rounds was that the car bomb was aimed at the nearby offices of Viacom, the broadcasting conglomerate which owns Comedy Central, the channel that recently censored an episode of satirical show South Park featuring a depiction of the Prophet Mohammed.

Last month, a US-based group called Revolution Muslim carried a posting on its website warning the makers of the show that they would "probably wind up like Theo Van Gogh." Viacom's head office is roughly half a block from the spot where the Nissan had been parked.

The failed attack unfolded shortly after 6.30pm on Saturday, when a police officer on horseback discovered the bomb following a tip-off from a vigilant local street vendor of t-shirts. It was one of the busiest times of the week in the area known as "the intersection of the world" because of its traffic-clogged streets and tourist-filled pavements.

The car, which had its engine on and hazard lights flashing, was awkwardly parked on 45th street, just north of Times Square and a short walk from several Broadway theatres which were starting to fill-up for the night. It smelled strongly of gunpowder and had smoke billowing from air vents near to its back seats.

As police and fire-fighters flooded the area, evacuating several major buildings, bomb squad officers broke the SUV's windows and used a robotic device to observe the bomb. They discovered that it had malfunctioned while in the process of detonating.

The car contained three propane tanks of a kind usually used for powering gas barbecues, together with two five-gallon cans of petrol, several over-the-counter fireworks, and two alarm clocks which had been adapted with batteries and electrical wire so that they worked as detonators. After it was eventually declared safe, surrounding streets were re-opened around 5.30am.

"We are very lucky. Thanks to alert New Yorkers and professional police officers, we avoided what could have been a very deadly event," said the city's Mayor, Michael Bloomberg. "It certainly could have exploded and had a pretty big fire and a decent amount of explosive impact."

Police have obtained security videos of the car driving to the scene, but are not thought to have got hold of footage of it actually being parked. The leading suspect is a white man in his 40s who was seen removing a dark shirt to reveal a red shirt, about half a block from the spot where the vehicle was left.

The car is now being examined at a local forensic laboratory, where investigators have got hold of hair and fibre samples together with a selection of fingerprints. It had fake number plates from Connecticut, and its serial numbers had apparently been filed away.

A gun locker found in the vehicle is also being examined. It is thought to have contained a large quantity of fertiliser.

Though Mr Bloomberg described the haphazard bomb as "amateurish", officials were anxious not to underplay the incident. New York's Fire Commissioner, Sal Cassano, said the bomb could have destroyed the front of a building, had it detonated. "This wasn't make-believe. This wasn't a false alarm. This was the real deal – to hurt people," he told reporters.

For anxious New Yorkers, the big question is now whether al-Qa'ida attempted the bombing as part of a renewed campaign to attack the city. Although the organisation has historically tended to carry out orchestrated operations involving multiple targets and several agents, Saturday's attempted attack bears at least some of its hallmarks.

In 2007, al-Qa'ida operatives left two cars packed with similar devices, made from propane tanks, petrol, and mobile-phone operated detonators, outside Tiger Tiger, a nightclub on Haymarket in London's West End. Neither successfully exploded, though, and the men responsible – Bilal Abdulla and Kafeel Ahmed – were arrested days later during a failed suicide attack on Glasgow airport.

Propane tanks are also commonly used by terrorists linked to al-Qa'ida to make car bombs in Iraq and the Middle East. And there have been signs recently that the group is once more targeting New York.

In February, Najibullah Zazi, a former airport shuttle driver, admitted attempting to make bombs to attack the city's subway system. In November, two former Brooklyn residents, Wesam el-Hanafi and Sabirhan Hasanoff, were charged with conspiring to provide computer advice to the organisation.

Explainer: Pakistani Taliban

The Pakistani Taliban claimed responsibility for the attack yesterday saying it was revenge for the death of its leader, Baitullah Mehsud, in a US drone strike last year. The claim also cited the killing by US and Iraqi forces of al-Qa'ida in Iraq last month.

At the time of his death, Mehsud had been Pakistan's most wanted man behind the insurgency that ravaged areas along the Afghan border.

The airstrike hit a compound belonging where the leader, who had a $5 million bounty on his head, reportedly was receiving treatment for his ailing kidneys.

There was no questioning his deadly effectiveness. He had used his mountainous tribal base to launch more than 200 suicide attacks killing more than 1,200 people before he died. In his last years, he had forged deep alliances with other militant groups in the region.

His successor was a young commander, Hakimullah Mehsud. It emerged last week that he was probably alive after reports that he had been killed in another missile strike.

The claim of responsibility for the Times Square attack posted on militant websites was treated with scepticism.

It would be a first for the group, which has never struck outside of South Asia, has no known global infrastructure and has previously claimed responsibility for an attack it was not involved with.

The nature of the 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, told Reuters.