US Secretary of State Antony Blinken headed Sunday to Qatar on his first trip since the Taliban takeover of Afghanistan as he seeks a united front with allies shaken by the chaos.

Qatar, a major US military base, has been the gateway for 55,000 people airlifted out of Afghanistan, nearly half the total evacuated by US-led forces after the Taliban's stunningly swift victory amid a US withdrawal.

Blinken will then head Wednesday to the US air base of Ramstein in Germany, a temporary home for thousands of Afghans moving to the United States, from which he will hold a virtual 20-nation ministerial meeting on the crisis alongside German Foreign Minister Heiko Maas.

Blinken said that in Qatar he will "express our deep gratitude for all that they're doing to support the evacuation effort" and meet rescued Afghans as well as US diplomats, who have relocated functions from the shuttered embassy in Kabul to Doha.

He will also speak to the Qataris about efforts alongside Turkey to reopen Kabul's ramshackle airport -- a pressing priority that is necessary for flying in badly needed humanitarian aid and evacuating remaining Afghans.

The Taliban have promised that they will keep letting Afghans leave if they want to -- one of the key issues that US allies expect to discuss in the talks in Germany.

The United States says it will monitor the Taliban's follow-up on commitments as it determines its future course with the hardline Islamists, whose 1996-2001 regime toppled by US forces was notorious for an ultra-austere interpretation of Islam that included public executions and a severe curtailing of women's rights.

But US officials said that Blinken does not plan to meet the Taliban, who have also made Doha their diplomatic base from which they negotiated the US pullout with the previous administration of Donald Trump.

"On the scope of high-level engagement with the Taliban, I would put that sort of in the recognition category to be considered or to be determined as we see what happens with their efforts to govern," said Dean Thompson, the top US diplomat for South and Central Asia.

European nations largely welcomed President Joe Biden's defeat of Trump, who delighted in needling allies, but leaders have openly questioned the handling of the pullout.

Britain's defense secretary, Ben Wallace, suggested that the United States is no longer a superpower and Armin Laschet, the leader of German Chancellor Angela Merkel's ruling party and candidate to succeed her, described the Afghanistan mission as "the biggest debacle" in NATO's history.

Biden, like Trump, argued that nothing more could be achieved in America's longest war and that the Afghan government, funded by the United States for 20 years, needed to fend for itself.