Gunmen killed a pro-government tribal elder, two of his sons and a brother on Friday in a troubled Pakistani tribal region where al Qaeda-linked militants are believed to have been hiding.

The unidentified assailants ambushed the car of Mirza Aalim Khan as he was travelling to Wana, the main town in the South Waziristan tribal region bordering Afghanistan, from a nearby village, witnesses said.

Khan was an influential man in Wazir tribe, one of the two dominant clans in the region inhabited by ethnic Pashtuns.

No one claimed responsibility for the attack, which came a day after a hand grenade was thrown into a Sunni Muslim mosque in the adjoining Kurram tribal region, killing two preachers.

A large number of al Qaeda linked militants are thought to be hiding in the rugged Waziristan region, about 400 km (250 miles) northwest of the capital Islamabad.

Hundreds of people have been killed in fierce clashes between security forces and militants in Waziristan in the past year.

PHOTO CAPTION

Soldiers of Pakistan militia stand at a check point after a mine explosion on the outskirts of Miran Shah in the Pakistan tribal area of Waziristan along the Afghanistan border Friday, July 22, 2005. (AP)