Provincial officials in western Afghanistan say at least 12 people were killed Sunday in factional fighting there.

The officials say clashes broke out in western Herat province between two local warlords, Amanullah Khan and Arbab Basir.

Earlier Sunday, NATO-led troops killed 15 suspected militants who ambushed a NATO convoy in southern Afghanistan.

The alliance said Sunday that the troops returned fire after they were attacked in Zabul province with small arms and rocket-propelled grenades.

It said two NATO vehicles were damaged in the attack.

NATO forces are encountering stiff resistance from Taleban insurgents in the south.

Some information for this report was provided by AFP and AP.