Panjshir has long been an anti-Taliban stronghold, and in recent weeks, opposition leaders there, along with officials from the fallen government, have been trying to marshal forces to hold off the Islamist militant group.

The Taliban, having secured a grip on the rest of the country, has responded quickly, with the group’s spokesman Zabihullah Mujahid saying in a statement Monday that resistance forces are “surrounded.” He added that the Taliban wants to avoid further fighting and to “resolve the issue peacefully through negotiations.”

But a Taliban fighter, speaking on the condition of anonymity because he wasn’t authorized to talk to the news media, told The Washington Post that the militant group’s leaders had decided to send forces to the valley because talks with the resistance group “couldn’t yield any results.”