Tank: Al Qaida-linked militants and Pakistani tribesmen fired rockets, mortar shells and automatic weapons yesterday in a region where officials say up to 177 people have been killed since last week.

The fighting showed the foreign militants, most of them Uzbeks from Central Asia, had alienated tribesmen who had earlier sheltered them in Pakistan's South Waziristan region after US backed forces chased them out of Afghanistan in late 2001.

Two children were killed overnight when a mortar bomb hit their home in Ghawakhawa, a village a few kilometres west of Wana, the main town in South Waziristan, witnesses said.

Interior Minister Aftab Ahmad Khan Sherpao said more than 50 people had been killed on Friday during clashes between Islamist militants and local Pashtun tribesmen.

Witnesses said the estimate was on the high side, but even by their reckoning the fighting has taken a heavy toll.

A resident of Shin Warsak, the village where fighting is concentrated, said he saw the bodies of 21 dead foreigners.

"Sporadic heavy fire continued throughout the night, but it has become more intense now in Shin Warsak," Noor Ali, another resident, said.

The clashes began after the Uzbek militants tried to assassinate a pro-government tribal leader last month, and flared again on Wednesday after attempts to broker a truce broke down.