"My group claims responsibility for the Karachi attack and we will carry out more such attacks, within 10 days," said Asmatullah Shaheen, one of the commanders of Tehrik-e-Taliban Pakistan (TTP), or Taliban Movement of Pakistan.
The prospect of more violence comes at a tough time for embattled Pakistani President Asif Ali Zardari. He already faces political pressure because corruption charges against some of his aides may be revived.
And Zardari has yet to formulate a more effective strategy against the Pakistani Taliban, despite relentless pressure from Washington, which wants his government to root out militants who cross over to attack US and NATO-led forces in Afghanistan and then return to their Pakistan strongholds.
The scale of his challenges was clear on Monday, when a suicide bomber defied heavy security around a Shi'ite procession, killing 43 people and triggering riots.
In a sign of mounting frustrations, Pakistani religious and political leaders called for a strike for Friday to condemn that attack, one of the worst in Karachi since 2007.
The bloodshed illustrated how the Taliban, whose strongholds are in the lawless northwest, have extended their reach to major cities in their drive to topple the government.
"The bombing itself was bad enough, but the violence that immediately erupted was also very well planned," said Sunni scholar Mufti Muneeb-ur-Rehman, who blamed Pakistani authorities for the chaos.
"We want the government not only to compensate those killed in the attacks, but also those who lost their livelihoods, and so we are calling for a complete strike on Friday," he said.
The Taliban campaign and their hardline brand of Islam -- which involves public hangings and whippings of anyone who disobeys them - angered many Pakistanis.
But the Karachi bomb suggested growing violence has raised suspicions of Pakistan's government.
"The government is using the Taliban as an excuse for everything that is happening anywhere in the country," said Noman Ahmed, who works for a Karachi clearing agency.
"The organized way that all this is being done clearly shows that the terrorists are being sponsored either by the government itself or some other state that wants to destabilize Pakistan."
Karachi: Pakistan's Taliban on Wednesday claimed responsibility for a suicide bombing that killed 43 people in the commercial capital Karachi, and threatened more attacks on the US ally.
First Published: Wednesday, December 30, 2009, 19:25