Afghan soldiers killed "dozens" of militants, including foreigners, in a clash on a highway in southern Zabul province on Thursday, the defence ministry said.
The clash broke out following reports of an ambush by the insurgents in Zabul, the ministry said in a statement.
"Thirty-four bodies of terrorists, among them a number of foreigners, have been collected from the battlefield," it said, adding some ammunitions were also seized.
It did not say if there were any casualties among the Afghan troops. The interior ministry said police forces were also involved and put the number of Taliban deaths as high as 70.
If confirmed, the losses would be the bloodiest for the militants in a single day in recent weeks in Afghanistan.
A provincial police official put the Taliban death toll at 37 and said two soldiers were wounded.
The Taliban, who lead the insurgency against the government and foreign troops, could not be contacted immediately for comment.
Violence has escalated in Afghanistan since 2006 when the Taliban, ousted from power in 2001, regrouped to drive out the troops and topple the Western-backed central government.
In neighbouring Ghazni province, Afghan security forces and NATO-led forces were still engaged in a joint operation they launched on Wednesday to retake a district from the Taliban, the alliance said.
Afghan and NATO officials said the militants had suffered some casualties.
Taliban militants captured the local government headquarters of the remote Ajristan district on Sunday, part of a campaign of seizing remote outposts and forcing thinly spread security forces to respond in a game of cat-and-mouse.
Separately, seven Afghan police were killed in two separate roadside bomb attacks in other parts of Afghanistan, officials said.
