KABUL: Militants ambushed a Nato coalition supply convoy in a mountainous area of western Afghanistan, sparking a three-hour firefight in which, Afghan officials said Thursday.

Najibullah Najibi, a spokesman for the Afghan National Army’s western region, said the battle raged Wednesday along a highway regularly used by coalition supply trucks in Bala Buluk district of Farah province.

“The fighting was intense and we sent in extra forces,” Najibi said.

There were varying estimates of the number of militants killed.

Raouf Ahmadi, a spokesman for the Afghan National Police in the west, said more than 30 militants were killed and 10 others were wounded.

Sayed Abdul Wahid, an official of the Arya security company, said his workers who were fighting with AK-47s were overpowered by militants using heavy weapons, including rocket-propelled grenades and machine guns.

He said five of his employees were killed and five others were wounded by insurgents who burned three vehicles in the convoy.