An Afghan official says forces at Bagram air base, home to a prison housing 5,000 inmates, have surrendered to the Taliban.
Bagram district chief Darwaish Raufi said Sunday that the surrender handed the one-time American base over to the insurgents.
The prison housed both Taliban and Islamic State group fighters.
It came as the Taliban entered the outskirts of Kabul.
Taliban fighters entered the outskirts of the Afghan capital on Sunday and said they were awaiting a “peaceful transfer” of the city after promising not to take it by force, but panicked residents raced to the leave, with workers fleeing government offices and helicopters landing at the US Embassy.
In a nationwide offensive that has taken just over a week, the Taliban has defeated, co-opted or sent Afghan security forces fleeing from wide swaths of the country, even though they had some air support from the US military.
On Sunday, they reached Kabul. Three Afghan officials told The Associated Press that the Taliban were in the districts of Kalakan, Qarabagh and Paghman in the capital.
The lightning speed of the push has shocked many and raised questions about why Afghan forces crumbled despite years of US training and billions of dollars spent. Just days ago, an American military assessment estimated it would be a month before the capital would come under insurgent pressure.
Taliban spokesman Suhail Shaheen told Qatar’s Al-Jazeera English satellite news channel that the insurgents are “awaiting a peaceful transfer of Kabul city.” He declined to offer specifics on any possible negotiations between his forces and the government.