US Secretary of State Antony Blinken said Tuesday that the Taliban had reiterated a pledge to allow Afghans to freely depart Afghanistan following his meeting with Qatari officials on accelerating evacuations.

US President Joe Biden has faced mounting pressure amid reports that several hundred people, also including Americans, had been prevented for a week from flying out of an airport in northern Afghanistan.

The Taliban told the United States that "they will let people with travel documents freely depart," Blinken told a news conference in Doha where he and Defense Secretary Lloyd Austin met their Qatari opposite numbers.

"We will hold them to that," he said.

Qatar said that Kabul airport, largely closed since the conclusion of Washington's chaotic withdrawal from the country at the end of August, would reopen soon, potentially opening an important corridor for Afghans seeking to leave.

"The entire international community is looking to the Taliban to uphold that commitment," Blinken said, referring to a UN Security Council resolution that urged safe passage.

Biden's senior cabinet members had dinner on arrival Monday with Qatar's ruler Emir Sheikh Tamim bin Hamad Al-Thani where they expressed Washington's thanks to Doha for its assistance with the Afghanistan airlift.

Extraordinary support

Qatar was the transit point for nearly half of the more than 120,000 people evacuated from Afghanistan in the final days of the 20-year US war as the Taliban took over.

Doha is the Taliban's international diplomatic base although Blinken's aides said he has no plans to meet them as Washington instead waits to judge the group's actions in power to determine the level of engagement.

The United States on Monday facilitated the evacuation of four Americans by land from Afghanistan, the first departures arranged by Washington since the military pullout.

A State Department official said the Taliban were aware of the operation and did not interfere.

But non-governmental organisations say that some 600 to 1,300 people -- including girls and US citizens -- are stuck at the airport in the northern city of Mazar-i-Sharif.

Marina LeGree, the founder and executive director of a small American non-governmental organisation active in Afghanistan, told AFP that the Taliban are not letting anyone through.

US officials say they no longer control the airspace in Afghanistan and that the main airport in Kabul, which the US military seized in August for evacuations, is in disrepair.

Qatari technical teams have deployed to Kabul to assess the viability of the airport and begin to prepare it for a return to operation to allow evacuations and the arrival of badly needed humanitarian supplies.

Blinken in his meeting with the Gulf state's ruler hailed "Qatar's extraordinary support in facilitating the safe transit of US citizens, our partners, and other Afghans at-risk," the State Department said.