Taliban and opposition forces battled on Saturday to control the Panjshir Valley north of Kabul, the last Afghan province holding out against the militant group, as the top US general warned of a "civil war" if the Islamists failed to consolidate power.

Both sides claimed to have the upper hand in Panjshir but neither could produce conclusive evidence to prove it. The Taliban, which swept through the country ahead of the final withdrawal of US-led forces this week, were unable to control the valley when they ruled Afghanistan from 1996 to 2001.

Taliban spokesperson Bilal Karimi said the districts of Khinj and...