Pakistani security officials and media gather at the site of a suicide bombing Sunday in Adazai town near Peshawar. (Mohammad Sajjad/Associated Press)A suicide bombing in northwestern Pakistan left 12 people dead and at least 25 others injured on Sunday, officials said.

The explosion ripped through a market 15 kilometres south of Peshawar in the town of Adazai, where the mayor, Abdul Malik, once supported the Taliban. He switched sides a couple of years ago and formed a militia to fight the militants.

The mayor is among the dead. Others killed include a young girl. At least nine of the injured were reported to be in critical condition.

Witnesses said the bomber arrived at the market in a car with five other people. One man came out of the vehicle, approached the mayor and exploded a bomb strapped to his body, they said. It was powerful enough to kill everyone in the immediate vicinity and destroy several nearby vehicles.

A purported Taliban commander has claimed responsibility for the blast. The man, who gave only one name, Omar, said in a telephone call from an undisclosed location that the group's local fighters carried out the attack.