The Taliban have taken control of a district near the Afghan capital, Kabul, a day before a three-day ceasefire is due to begin.
The militants confirmed on Tuesday that they had captured Nerkh district in Wardak province in a "surprise attack".
Nerkh is the second district in a week to fall to the Taliban.
Afghanistan is seeing increasing violence as the US and Nato prepare to pull out remaining troops by 11 September.
"The district centre of Nerkh in Maidan Wardak province, the police headquarters, the intelligence department and a large army base there were all captured," Taliban spokesman Zabihullah Mujahid said on Twitter.
He added that "many enemy soldiers" had been killed or wounded.
Abdul Rahman Tariq, governor of the province, confirmed that the district had been captured and said Afghan troops had "tactically retreated from the district".
The defence ministry said on Wednesday that it would launch an offensive to gain back the district.
The capture of Nerkh comes after militants took control of Borka district in the northern province of Baghlan on 5 May.
A three-day ceasefire, coinciding with the Muslim festival Eid, is set to begin on Thursday
The Taliban have stepped up assaults on the Afghan government this month.
Just days ago, at least 68 people, mainly students, were killed in a bombing outside a school in Kabul. At least 165 others were injured. The Afghan government blamed Taliban militants for the attack, but the group denied involvement.
President Joe Biden says the US pull-out is justified as US forces have made sure the country cannot again become a base for foreign jihadists to plot against the West.
A senior United Nations official warned last year that al-Qaeda, which was hosted by the Taliban after the 9/11 attacks in the US, was still "heavily embedded" within Taliban militants in Afghanistan.
Afghan President Ashraf Ghani says government forces are now fully capable of keeping insurgents at bay.
However, not everyone shares the optimism. Many believe the withdrawal could plunge the country back to the dark days of the Taliban era.