The Taliban claimed Friday to have captured Kandahar, Afghanistan's second-largest city, which would leave just the capital and pockets of other territory in the government's hands.
"Kandahar is completely conquered. The Mujahideen reached Martyrs' Square in the city," a Taliban spokesman tweeted on an officially recognised account -- a claim backed by a resident, who told AFP government forces appeared to have withdrawn en masse to a military facility outside the city.
The claim was backed up by a resident, who told AFP government forces appeared to have withdrawn en masse to a military facility outside the southern city.
The government has now effectively lost control of most of the country, following an eight-day blitz into urban centres by the Taliban that has left the Afghan government and its US backers stunned.
The offensive was launched after the United States and its allies all but withdrew its forces from Afghanistan, with President Joe Biden determined to end two decades of war by September 11.
Biden has insisted he has no regrets with his decision, but the speed and ease of the Taliban's urban victories in recent days has been a surprise and forced new calculations.
Washington and London announced on Thursday night moves to quickly pull out their embassy staff and other citizens from the capital.
"We are further reducing our civilian footprint in Kabul in light of the evolving security situation," US State Department spokesman Ned Price told reporters, while noting the embassy would remain open.
"This is not abandonment. This is not an evacuation. This is not the wholesale withdrawal."
The Pentagon said 3,000 US troops would be deployed to Kabul within the next 24 to 48 hours, underscoring that they would not be used to launch attacks against the Taliban.
Britain's Defence Secretary Ben Wallace said London would send 600 of its own troops to evacuate its nationals and former Afghan staff.
Price said the United States would also start sending in daily flights to evacuate Afghan interpreters and others who assisted the Americans.
'Laid down their arms'
The conflict has escalated dramatically since May, when US-led forces began the final stage of their troop withdrawal.
After months of taking what were considered less strategically important rural areas, the Taliban zeroed in on the cities.
In the past week, the insurgents have taken over a dozen provincial capitals and encircled the biggest city in the north, the traditional anti-Taliban bastion of Mazar-i-Sharif, which is now one of the few holdouts remaining.
Pro-Taliban social media accounts have boasted of the vast spoils of war their fighters had recovered in recent days.
They have posted photos of armoured vehicles, heavy weapons and even a drone seized by the insurgents at abandoned military bases.
After being under siege for weeks, government forces on Thursday pulled out of Herat -- an ancient silk road city near the Iranian border -- and retreated to a district army barracks.
Herat resident Masoom Jan told AFP the city's fall had been abrupt, saying the Taliban "entered the city in rush. They raised their flags in every corner."
On Thursday, the interior ministry also confirmed the fall of Ghazni, about 150 kilometres (95 miles) from Kabul and along the major highway to Kandahar and the Taliban heartlands in the south.
A security source told AFP that Qala-i-Naw, capital of Badghis province in the northwest, also capitulated on Thursday.