Fighting between local and Central Asian militants escalated in northwestern Pakistan on Wednesday, as the death toll from three days of clashes rose to more than 100, officials said.

Militants were exchanging mortar, rocket and assault rifle fire in four areas of South Waziristan, where the clashes broke out Monday. The government has been urging tribesmen to move against Al Qaeda-linked fighters in the region.

Senior government and intelligence officials said about 105 people had died in the fighting, mostly Uzbeks and Chechens. The officials, who requested anonymity because of the sensitivity of the issue, said their information came from army commanders and intelligence agents in the region.

Army spokesman Maj. Gen. Wahid Arshad confirmed that fighting was continuing Wednesday, but refused to give any casualty figures as the army was not involved.

It was not possible to confirm the death toll independently as phone lines to South Waziristan were down and journalists have minimal access to the lawless region.

Pakistan has hailed the fighting as a success of their controversial aim of getting local tribesmen rather than security forces to crack down on foreign militants. But some observers see it primarily as a factional struggle between rival militant groups in a lawless region near Afghanistan, where sympathies for the hard-line Taliban militia run high.

"It is the result of government policy that the local tribesmen are acting against foreign militants," Interior Minister Aftab Khan Sherpao told The Associated Press.

Senior Pakistani intelligence and military officials, speaking on condition of anonymity because they were unauthorized to make comments to media, said most of the casualties were Uzbeks and local supporters, and the rest local militants led by Maulvi Nazir.

The officials described Nazir as "pro-government," though he is well-known as a Taliban sympathizer.

The intelligence official said Nazir's men had given an ultimatum to the Uzbeks to leave their territory by midnight Tuesday, and had resumed attacks Wednesday after that deadline passed.

The tribesmen have handed over 46 militants, many of them Uzbeks, to Pakistani security forces in the region's main town of Wana, and another 68 Uzbeks were still in the custody of the tribesmen, the official said.

While the motive behind the current fighting in South Waziristan remains hazy, the casualties suffered by the Uzbek fighters could ease pressure on Pakistan, which is facing fresh U.S. concern that Al Qaeda is regrouping in an area. Waziristan is also viewed as a haven for Taliban fighters attacking NATO and U.S. forces across the border.