The attacker blew himself up as a convoy of civilians escorted by security forces passed, police said. The blast also wounded 25 people.

Suicide bombings have eased in recent weeks but it's not clear whether that is because security has improved after military gains against the Taleban, or if the insurgent are merely regrouping for more attacks.

Pakistan has launched two major offensives in the northwest over the past year against homegrown Taleban militants who want to topple the US-backed government of President Asif Ali Zardari.

The operations have destroyed militant bases, and Taleban leader Hakimullah Mehsud is widely believed to have been killed in a US drone strike in January. His predecessor was killed in a similar strike in August.