KABUL, Afghanistan — Taliban militants overran a cluster of government outposts in northwestern Afghanistan on Friday, leaving more than a dozen Afghan soldiers dead, including several troops from an elite police unit, officials said.

The brutal fighting came a day after the United States and the Taliban ended their sixth round of peace negotiations and the militant group said that it would continue to mount attacks, including ones like the car bomb directed at two Western aid organizations in Kabul on Wednesday that killed nine and wounded at least 20.

Col. Qais Mangal, a spokesman for Afghanistan’s Defense Ministry, said the Taliban had attacked two outposts in the Murghab district of Badghis Province that are shared by the army, the police and the National Directorate of Security. He said the Afghan military had sent reinforcements as the fighting continued.

“Unfortunately, the Afghan forces suffered casualties, but there isn’t any information about the exact number,” Colonel Mangal said.