According to the sources, The Taliban killed at least 13 Afghan soldiers in battles that raged for three days in western Badghis province where insurgents overran several army checkpoints.
The provincial governor's spokesman Jamshid Shahabi said the fate of a dozen other soldiers is unknown.
He says the fighting erupted on Saturday in Bala Murghab district.
The military carried out several airstrikes and dispatched reinforcement.
Shahabi says 42 insurgents were killed and 15 troops were wounded in the fighting.
The officials say the fighting has subsided with only sporadic clashes on Tuesday in remote areas of the province.
The Taliban have claimed responsibility for the attack.