The blast took place at a busy vegetable market in the country's northwestern region along the Afghan border.
At least 20 people were killed and 40 injured when an explosion ripped through a crowded market in Pakistan's northwestern tribal region on Saturday.
The blast took place at a vegetable market in Parachinar city, the capital of the Kurram tribal district close to the Afghan border.
"20 people have been martyred," the Pakistan military said in a short statement, adding that the injured had been taken to military and civil hospitals in the region's main city of Peshawar.
Sajid Hussain Turi, a member of the National Assembly from the region, said an improvised explosive device (IED) had been planted in a pile of tomatoes and detonated as people gathered in the market.
Kurram is one of Pakistan's seven semi-autonomous tribal districts which are governed according to local laws and customs.
Taliban militants have been active around Parachinar in the past, and the town has also suffered sectarian tension between Sunni and Shia Muslims.