KABUL: Taliban insurgents entered the Afghanistan capital Kabul on Sunday, an interior ministry official said, as the United States evacuated diplomats from its embassy by helicopter.

The Taliban were on the brink of total victory in Afghanistan on Sunday, with their fighters ordered to wait on the outskirts of the capital and the government conceding it was preparing for a "transfer of power".

The Taliban's militants surrounded Kabul following an astonishingly quick rout of government forces, who proved incapable of holding onto territory without US military support.

The fall of Kabul will see the Taliban take back power two decades after US-led forces toppled it in the wake of the September 11, 2001 attacks.

"The Islamic Emirate instructs all its forces to stand at the gates of Kabul, not to try to enter the city," a spokesman for the Taliban tweeted as residents reported insurgents on the outskirts of the city.

په کابل ښار کې د جګړې نه کولو په اړه د اسلامي امارت اعلامیه https://t.co/DZWnmSsMfd pic.twitter.com/AFkV9DlDkN

— Zabihullah (..ذبـــــیح الله م ) (@Zabehulah_M33) August 15, 2021

"Until the completion of the transition process, the responsibility for the security of Kabul is with the other side (the Afghan government)".

U.S. officials said the diplomats were being ferried to the airport from the embassy in the fortified Wazir Akbar Khan district. More American troops were being sent to help in the evacuations after the Taliban's lightning advances brought them to Kabul in a matter of days.

Just last week, a U.S. intelligence estimate said Kabul could hold out for at least three months.

"Core" U.S. team members were working from the Kabul airport, a U.S. official said, while a NATO official said several EU staff had moved to a safer, undisclosed location in the capital.

A Taliban official told Reuters the group did not want any casualties as it took charge but had not declared a ceasefire.

There was no immediate word on the situation from President Ashraf Ghani, who said on Saturday he was in urgent consultations with local leaders and international partners on the situation.

Earlier on Sunday, the insurgents captured the eastern city of Jalalabad without a fight, giving them control of one of the main highways into landlocked Afghanistan. They also took over the nearby Torkham border post with Pakistan, leaving Kabul airport the only way out of Afghanistan that is still in government hands.

The capture of Jalalabad followed the Taliban's seizure of the northern city of Mazar-i-Sharif late on Saturday, also with little fighting.

"There are no clashes taking place right now in Jalalabad because the governor has surrendered to the Taliban," a Jalalabad-based Afghan official told Reuters. "Allowing passage to the Taliban was the only way to save civilian lives."

A video clip distributed by the Taliban showed people cheering and shout Allahu Akbar - God is greatest - as a convoy of pick-up trucks entered the city with fighters brandishing machine guns and the white Taliban flag.

After U.S.-led forces withdrew the bulk of the their remaining troops in the last month, the Taliban campaign accelerated as the Afghan military's defences appeared to collapse.

President Joe Biden on Saturday authorised the deployment of 5,000 U.S. troops to help evacuate citizens and ensure an "orderly and safe" drawdown of military personnel. A U.S. defence official said that included 1,000 newly approved troops from the 82nd Airborne Division.

Taliban fighters entered Mazar-i-Sharif virtually unopposed as security forces escaped up the highway to Uzbekistan, about 80 km (50 miles) to the north, provincial officials said. Unverified video on social media showed Afghan army vehicles and men in uniforms crowding the iron bridge between the Afghan town of Hairatan and Uzbekistan.

Two influential militia leaders supporting the government - Atta Mohammad Noor and Abdul Rashid Dostum - also fled. Noor said on social media that the Taliban had been handed control of Balkh province, where Mazar-i-Sharif is located, due to a "conspiracy."

POPULARLY ACCEPTED

In a statement late on Saturday, the Taliban said its rapid gains showed it was popularly accepted by the Afghan people and reassured both Afghans and foreigners that they would be safe.

The Islamic Emirate, as the Taliban calls itself, "will, as always, protect their life, property and honour, and create a peaceful and secure environment for its beloved nation," it said, adding that diplomats and aid workers would also face no problems.

Early on Sunday, refugees from Taliban-controlled provinces were seen unloading belongings from taxis and families stood outside embassy gates, while the city's downtown was packed with people stocking up on supplies.

Hundreds of people slept huddled in tents or in the open in the city, by roadsides or in car parks, a resident said on Saturday night. "You can see the fear in their faces," he said.

Biden said his administration had told Taliban officials in talks in Qatar that any action that put U.S. personnel at risk "will be met with a swift and strong U.S. military response."

He has faced rising domestic criticism as the Taliban have taken city after city far more quickly than predicted. The president has stuck to a plan, initiated by his Republican predecessor, Donald Trump, to end the U.S. military mission in Afghanistan by Aug. 31.

Biden said it is up to the Afghan military to hold its own territory. "An endless American presence in the middle of another country's civil conflict was not acceptable to me," Biden said on Saturday.

Qatar, which has been hosting so-far inconclusive peace talks between the Afghan government and the Taliban, said it had urged the insurgents to cease fire. Ghani has given no sign of responding to a Taliban demand that he resign as a condition for any ceasefire.