KHAR (Pakistan) - PRO-GOVERNMENT tribesmen killed 23 militants in clashes in Pakistan's volatile northwest in the latest violence between tribal militias and Taleban insurgents, a government official said on Tuesday.

The fighting took place in the village of Ambar in the Mohmand region, part of the lawless tribal belt along Pakistan's border with Afghanistan where top Taleban and Al-Qaeda leaders are believed to be hiding.

Syed Ahmad Jan, a senior regional administrator, said local tribal militia asked the militants to leave the area late Monday.

The militants refused and opened fire, sparking a gun battle that was still raging Tuesday morning, Jan said.

Pakistan's government has encouraged tribesman in the semiautonomous frontier region to form local militias - known as lashkars - to repel Taleban militants blamed for attacks in Pakistan and in neighbouring Afghanistan. The militias carry out patrols and have been pursuing remnants of Taleban who had tried to expand their influence into the area.

Such groups have been set up in several regions but face stiff Taleban resistance.

Pakistan's military also has carried out operations of its own against militants in the volatile northwest, and is readying another major offensive against Taleban fighters in the South Waziristan region of the tribal belt.

The US strongly supports Islamabad's efforts to confront the insurgents, seeing them as a test of nuclear-armed Pakistan's resolve to tame Islamist militancy in the country. -- AP