Fighting between local and foreign militants near the Afghan border killed 52 people Friday, a senior official said, a flare-up in a conflict that has pitted Pakistanis against suspected Al Qaeda-linked extremists.

Interior Minister Aftab Khan Sherpao said 45 Uzbek militants and seven tribesmen died in battles in South Waziristan, a lawless region used as a rear base by Taliban militants fighting in Afghanistan and where the United States fears that Al Qaeda is regrouping.

Sherpao told The Associated Press that the latest deaths bring to 213 the number of people killed since the fighting began last week, including 177 Uzbeks and their local allies.

The minister said the conflict intensified Friday after foreigners failed to comply with an ultimatum from tribal elders to leave their territory. Security officials said tribal militias had fired rockets at the hideouts of the foreigners in several locations.

An aide to Maulvi Nazir, the leader of the purportedly pro-government side in the conflict, said earlier Friday that they had killed 35 Uzbeks and lost 10 of their own men. He said both sides were using heavy weapons. The aide, who spoke to AP by telephone, asked for anonymity to prevent enemies from identifying him.

South Waziristan is generally off-limits to journalists, making it hard to verify reports of the fighting.

Under pressure from the United States to do more against the Taliban and Al Qaeda, the government has claimed that the violence in South Waziristan vindicates its policy of using traditional leaders, and not the army, to combat militancy along the border.

The government claims Nazir, a tribal chief previously aligned with the Taliban, has come over to their side.

Some analysts, however, say militants with links to Taliban and Al Qaeda are involved on both sides of the current conflict, which also pits local tribes against each other, and that blood feuds could deepen insecurity in a region viewed as a possible hiding place for Usama bin Laden and Ayman al-Zawahiri.

Hundreds of Central Asian and Arab militants linked to Al Qaeda fled to this semiautonomous region after the collapse of the Taliban regime in Afghanistan and forged alliances with local tribes. Other Uzbek Islamists opposed to the regime of President Islam Karimov in their homeland have reportedly since joined them from Uzbekistan.

As part of its support of the U.S.-led war on terror, Pakistan launched military operations in 2004 to wipe the foreign militants out. They succeeded in busting camps used by Al Qaeda, but suffered hundreds of casualties and failed to expel the foreign fighters.

More recently, Pakistan has cut deals with pro-Taliban militants and urged local tribal elders to police the region themselves.