A suicide bomber has set off a blast, killing up to 15 people in the town of Bannu in northwestern Pakistan, police said.

The bomb on Monday, thought to be targeting a military convoy, was apparently hidden in an autorickshaw that police were checking, Habib Khan, a police officer, said.

Major-General Waheed Arshad, a military spokesman, said 11 civilians and four policemen had been killed in the suicide blast.

The blast was triggered by a passenger wearing a woman's burqa.

"A burqa-clad bomber - either it was a woman or a man in a burqa - set off explosives when police approached," Javed Iqbal Cheema, an interior ministry spokesman, said.

A police official said the blast went off near a bus stand and 19 people were also wounded.

Bannu, a major garrison town near Pakistan's troubled tribal areas, borders Afghanistan.

Pakistan's military has suffered a string of deadly attacks since a peace treaty with tribal elders broke down and government troops stormed the Red Mosque in Islamabad in July.

PHOTO CAPTION

A suicide bomber kills up to 15 people in the town of Bannu in northwestern Pakistan. (BBC)

Al-Jazeera