Islamabad: A car bomb went off in a market in the restive tribal belt of northwest Pakistan on Friday, killing at least 11 people and injuring over 30 others, police said.

The explosives-packed vehicle was detonated outside a mosque in a crowded market in Parachinar, the main town of Kurram tribal region, which has been rocked by sectarian violence over the past few years.

Witnesses said several shops and vehicles were destroyed by the blast.

Most of the casualties were civilians, they said.

The injured were taken to a nearby 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 may be linked to sectarian tensions in the area.

Some reports said a suicide attacker was involved in the bombing but this could not immediately be confirmed.

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.