KABUL: The Taliban seized more major cities on Friday as they raced to take full control of Afghanistan and inched closer to Kabul, with the United States and Britain deploying thousands of troops to evacuate their citizens from the capital.

Taliban said they had captured the city's long-time strongman Ismail Khan, who helped lead the defence of the provincial capital along with his militia fighters.

The warlord's spokesman later confirmed Khan had been allowed to return to his residence following negotiations with the insurgents.

The evacuation orders came as the Taliban took control of Kandahar -- the nation's second-biggest city -- in the insurgency's heartland, leaving only Kabul and pockets of other territories in government hands.

The Taliban also captured the capital of Logar province, just 50kms (30 miles) from Kabul, with a local lawmaker saying the insurgents were in complete control of Pul-e-Alam city.

Earlier Friday, officials and residents in Kandahar told AFP that government forces had withdrawn en masse to a military facility outside the southern city.

"Kandahar is completely conquered. The Mujahideen reached Martyrs' Square," a Taliban spokesman tweeted, referring to a city landmark.

Hours later, the Taliban said they had also taken control of Lashkar Gah, the capital of neighbouring Helmand province.

A security source confirmed the fall of the city, telling AFP that the Afghan military and government officials had evacuated Lashkar Gah after striking a local ceasefire deal with the militants.

The government has now effectively lost most of the country following an eight-day blitz into urban centres by the Taliban that has also stunned Kabul's American backers.

The first wave of the offensive was launched in early May after the United States and its allies all but withdrew their forces from Afghanistan, with President Joe Biden determined to end two decades of war by September 11.

   - 'Not abandonment' -

Biden insists he does not regret 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 plans late Thursday to pull out their embassy staff and 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 they would not be used to launch attacks against the Taliban.

NATO was also set to hold an urgent meeting later on Friday about the deteriorating situation, diplomatic and official sources told AFP.

Secretary General Jens Stoltenberg will lead discussions with envoys from the 30 allies, with one source saying it would focus on evacuation planning.

   **- Taliban flags across Kandahar -**

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.

The insurgents have taken over more than a dozen provincial capitals in the past week 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.

In Kandahar, resident Abdul Nafi told AFP the city was calm after the government forces pulled out early Friday.

"I came out this morning, I saw Taliban white flags in most squares of the city... I thought it might be the first day of Eid."

Pro-Taliban social media accounts have boasted of the vast spoils of war captured by the insurgents, posting photos of armoured vehicles, heavy weapons, and even a drone seized by their fighters 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.

On Thursday, the interior ministry also confirmed the fall of Ghazni, opening a corridor along the major highway to Kabul from the Taliban heartlands in the south.

As the rout unravelled, three days of meetings between key international players on Afghanistan ended in Qatar without significant progress Thursday.

In a joint statement, the international community, including the United States, Pakistan, the European Union, and China, said they would not recognise any government in Afghanistan "imposed through the use of military force."