PESHAWAR: Pakistan's main Taliban faction on Wednesday claimed responsibility for a suicide attack that killed 43 people at a Shiite parade in Karachi, one of the group's most-wanted commanders told AFP.

A bomber detonated explosives strapped to his body as crowds marched down Mohammad Ali Jinnah Road in the heart of Pakistan's largest city on Monday, turning the Shiites' holiest day of Ashura into a bloodbath.

It was the deadliest attack in Karachi in more than two years and one of the deadliest single sectarian-linked attacks in the conservative Muslim country's history.

Pakistan has been pressing a major offensive against Tehreek-e-Taliban Pakistan (TTP) in its South Waziristan stronghold on the Afghan border since October.

Any involvement by the network in such a deadly attack, hundreds of miles away from its tribal headquarters, would suggest that TTP capabilities are still potent despite the two-month operation.

"We carried out the suicide bombing in Karachi," Asmatullah Shaheen, a top militant commander based in South Waziristan, told AFP by telephone from an undisclosed location.

Shaheen, whose name is on a government list of 19 most-wanted militants, said "he (the bomber) was our man; his name was Hasnain Muawia".

"We did it to protect the honour of the companions of the holy prophet," he said in reference to a centuries old dispute between Sunni Muslims, who dominate the Taliban, and Shiite Muslims over the succession to the Prophet Mohammed.

"We will carry out more such attacks and also target government installations," Shaheen said.

The bombing and ensuing arson by furious mourners underscored the extent of the volatility in nuclear-armed Pakistan, where militant attacks have killed more than 2,760 people since July 2007 and which Washington has put on the frontline of its war on Al-Qaeda.

Pakistan posted a 10-million-rupee (118,690 dollar) bounty for Shaheen's capture dead or alive when it published a list last month of its most-wanted TTP warlords, which offered combined rewards of five million dollars.

Led by Hakimullah Mehsud since a US drone attack killed founder Baitullah Mehsud in August, TTP has claimed and been blamed for some of the worst attacks in Pakistan.

Monday's attack sparked riots as mourners went on the rampage, throwing stones at ambulances, torching cars and buildings and reducing shops to charred wreckage. Firefighters continued to drench the flames Wednesday.

Sectarian violence periodically flares in Pakistan between Shiites, who beat and whip themselves in religious fervour during Ashura, and the country's majority Sunnis, who oppose the public display of grief.

Shiites account for about 20 percent of Pakistan's mostly Sunni Muslim population of 167 million. More than 4,000 people have died in outbreaks of sectarian violence in Pakistan since the late 1980s.