The United Nations has begun moving some staff out of Afghanistan, a spokesperson said Wednesday, as foreign nationals scramble to leave the country after the Taliban's return to power.

UN spokesman Stephane Dujarric told reporters the world body was relocating about 100 employees to Almaty in Kazakhstan.

"This is a temporary measure intended to enable the UN to keep delivering assistance to the people of Afghanistan with the minimum of disruption while, at the same time, reducing risk to UN personnel," he said.

Dujarric did not specify whether the staff being relocated were international or Afghan or a mixture of both.

If they are international then it would represent about one third of foreign staff at the United Nations Assistance Mission in Afghanistan (UNAMA).

A Taliban fighter holds an RPG as he stands guard outside the interior ministry in the Afghan capital Kabul
A Taliban fighter holds an RPG as he stands guard outside the interior ministry in the Afghan capital Kabul AFP / Javed Tanveer

UNAMA employs around 300 foreigners at its headquarters in Kabul as well as more than 700 Afghan nationals.

"The UN is committed to staying and delivering in support of the Afghan people in their hour of need," Dujarric said.

"The remote presence will provide close support to the UN family's continuing work on the ground in Afghanistan," he added.

The Taliban took control of Afghanistan on Sunday, nearly two decades after they were ousted by a US-led invasion in the wake of the September 11, 2001 attacks.

Their sudden victory, which comes as America withdraws from the country following a 20-year-war, has sparked chaos at Kabul's airport where US and allied leaders are trying to safely extract thousands of citizens and allies.