Afghan officials say a NATO supply convoy came under heavy fire in mountainous western Afghanistan late Wednesday, sparking a gunbattle in which at least five Afghan security guards, an Afghan soldier and 14 attackers were killed.

The officials say the firefight in Farah province was intense and raged for hours following the ambush by a large group of insurgents.

There were varying estimates of the number of militants killed. Several media outlets said at least 28 insurgents died in the fighting.

Separately, NATO said two of its service members died in southern Afghanistan Thursday. A NATO statement said one coalition soldier was killed in a bomb blast, and the other died as a result of a non-battle related injury.