PESHAWAR, Pakistan: Two bombs exploded in a market in the northwestern Pakistani city of Peshawar yesterday, killing six people, and gunmen on rooftops ambushed police as they arrived at the scene, officials and witnesses said.

The attack came hours after the Pakistani Taliban claimed responsibility for Wednesday's suicide car-bomb and gun attack in the eastern city of Lahore that killed 24 people, saying it was in revenge for an army offensive in the Swat region.

Militant violence in nuclear-armed Pakistan, an important US ally, has surged since mid-2007, with numerous attacks on the security forces, as well as on government and Western targets, and the Taliban yesterday threatened more violence.