The Taliban have taken complete control of Panjshir province, the last area in Afghanistan being held by resistance forces, the group's spokesman, Zabihullah Mujahid, said on Monday.
Pictures on social media showed Taliban members standing in front of the gate of the Panjshir provincial governor's compound.
In a statement, spokesman Zabihullah Mujahid said Panjshir has been "completely conquered," assuring residents that they would be safe.
"We give full assurance to the honourable people of Panjshir that they will not be discriminated against, they are all our brothers ...," he said.
Anti-Taliban forces in the northern province were led by former vice president Amrullah Saleh, and the son of late mujahideen commander Ahmad Shah Massoud.
The Taliban are yet to finalise their new regime after rolling into Kabul three weeks ago at a speed.
Afghanistan's new rulers have pledged to be more "inclusive" than during their first stint in power, which also came after years of conflict -- first the Soviet invasion of 1979, and then a bloody civil war.
They have promised a government that represents Afghanistan's complex ethnic makeup -- though women are unlikely to be included at the top levels.
Women's freedoms in Afghanistan were sharply curtailed under the Taliban's 1996-2001 rule.
This time, women will be allowed to attend university as long as classes are segregated by sex or at least divided by a curtain, the Taliban's education authority said in a lengthy document issued on Sunday.
But female students must also wear an abaya (robe) and niqab (face-veil), as opposed to the even more conservative burqa mandatory under the previous Taliban regime.
As the Taliban come to grips with their transition from insurgency to government they are facing a host of challenges, including humanitarian needs for which international assistance is critical.
UN humanitarian chief Martin Griffiths has arrived in Kabul for several days of meetings with the Taliban leadership, which has promised to help.
"The authorities pledged that the safety and security of humanitarian staff, and humanitarian access to people in need, will be guaranteed and that humanitarian workers -- both men and women -- will be guaranteed freedom of movement," a statement from UN spokesman Stephane Dujarric said.
The Taliban spokesman tweeted that the group's delegation assured the UN of cooperation.
The international community is coming to terms with the new Taliban regime with a flurry of diplomacy.
US Secretary of State Antony Blinken is due Monday in Qatar, a key player in the Afghan saga.
Qatar, which hosts a major US military base, has been the gateway for 55,000 people airlifted out of Afghanistan, nearly half the total evacuated by US-led forces after the Taliban takeover on August 15.
Blinken will also speak to the Qataris about efforts alongside Turkey to reopen Kabul's airport, which is necessary for flying in badly needed humanitarian aid and evacuating remaining Afghans.
Blinken will then head Wednesday to the US airbase in Ramstein, Germany, a temporary home for thousands of Afghans moving to the United States, from which he will hold a virtual 20-nation ministerial meeting on the crisis alongside German Foreign Minister Heiko Maas.
