Separately, the Afghan government said it was checking reports by locals saying some 40 Afghan civilians were killed in a raid by foreign forces in Sangin district of southern Helmand province on Friday.

In Nuristan’s Barg-e Matal, dozens of Taliban fighters and up to six Afghan police were killed during days of clashes before the district fell to the Taliban overnight.

Barg-e Matal is important for the government and militants because of its location and has regularly changed hands.

Lying near the border with Pakistan, the rugged district has been used as a supply route for arms and fighters for the Taliban in three provinces, most importantly for Badakhshan where the Taliban have mounted a series of deadly attacks recently.

Afghan police forces withdrew from Barg-e Matal to avoid high casualties and in the face of sustained Taliban pressure after days of skirmishes, interior ministry spokesman Zemarai Bashary told reporters.

“Right now the police forces in Nuristan are working to recapture it,” he said.

The Taliban have yet to comment about the fall of the district and the reported losses in their ranks.

In Helmand province, where the Taliban insurgency is strongest, Bashary said provincial authorities were checking reports by residents that dozens of civilians were killed in a raid by foreign forces on Friday.