At least 15 people, including four policemen, were killed when a suicide bomber blew himself up at a market in Pakistan's North West Frontier Province on Monday morning. 

Defence spokesman Wahid Rashid told reporters that 11 civilians along with four policemen were killed in the bombing at the local market in Bannu, a garrison town.

The militant apparently blew himself up when police tried to intercept him, local reports said.

Bannu has been witnessing a spate of suicide attacks since the military raid on Islamabad's Lal Masjid in July in which nearly 100 extremists were killed.