At least 21 people were killed and 45 others injured on Friday when a suicide bomber blew himself up outside a mosque in Pakistan's restive northwestern tribal region, police said.
The attacker, who was on a motorcycle, detonated his explosive vest outside the mosque in a crowded market at Parachinar, the main town of Kurram tribal region, which has been rocked by sectarian violence over the past few years.
Officials told the media that the local hospital had received 21 bodies and 45 injured persons.
An emergency was declared at the hospital.
The officials said they feared the casualties could rise as the bomber had struck at a time when the market was full of people.
The bomber blew himself up before the weekly Friday prayers.
Earlier reports had said a car bomb had gone off at the market.
Witnesses said several shops and vehicles were destroyed by the blast. Most of the casualties were civilians, they said.
The injured were taken to hospital by local residents in private vehicles. Security forces cordoned off the site of the attack and launched a search operation.
No group claimed responsibility for the attack.
Officials said the attack might be linked to sectarian tensions. Hundreds of people have died in clashes between rival Shia and Sunni tribesmen in Kurram Agency over the past four years.
The situation in the region was exacerbated after Taliban fighters began backing the Sunni tribesmen.