The powerful explosion occurred in the bazar in Parachinar, the main town in Kurram Agency, this evening. Ten people were killed instantly and more than 25 others injured, officials of the local political administration said.
The injured were taken to a hospital in Parachinar. Soon after the blast, security forces cordoned off the area and launched a search operation.
Earlier in the day, two members of the minority Shia community were killed and six more injured when a pick-up truck hit a landmine near Khar Pata area.
Unlike other semi-autonomous tribal regions in northwest Pakistan, Shias are in a majority in Kurram Agency. Sporadic incidents of violence have rocked the region despite a fragile accord between the rival tribesmen.