A suicide bomber threw himself at a passing para-military convoy near a crowded market killing 41 people and wounding 50 in Shangla district in Pakistan's Malakand division, two days after Taliban militants stormed the army headquarters in Rawalpindi.
Witnesses said the suicide bomber blew himself up near a security forces vehicle as it was passing through a security check post in the market at Alpuri and most of the dead were civilian passers by.
The attack occurred close to a police station.
North West Frontier Province Information Minister Mian Iftikhar Hussain said 41 people, including six security personnel, were killed in the blast. Police officials said over 50 people, including soldiers and policemen, were injured.
"The condition of five of the injured security personnel was reported to be serious," a local police official told private TV channel.
The official said the target of the bomber was the security convoy, but lots of civilians were killed as they were huge number of people in the market at the time of the blast.
No group claimed responsibility for the attack though Taliban has vowed to carry out more such strikes to take revenge for the death of their leader Baittulla Mehsud.