More than 250 foreign nationals have left Afghanistan in the past three days, said Zalmay Khalilzad, Washington's special envoy and the architect of an often criticised deal with the Taliban.
The deal signed last year provided for the safe withdrawal of US and NATO troops but critics say it was heavily weighted in favour of the hardline-Islamist movement.
In a series of tweets, Khalilzad praised both Qatar, whose national airline carried out the flights, and the "Taliban's cooperation in this important effort,'' for the recent departure of foreign nationals from Afghanistan.
"We will continue to engage the government of Qatar, the Taliban, and others to ensure the safe passage of our citizens, other foreign nationals, and Afghans that want to leave,'' Khalilzad tweeted.
However, hundreds of Afghans, including US citizens and green card holders, remain stranded in the northern city of Mazar-e-Sharif, waiting to be evacuated but stopped by Taliban rulers demanding travel documents.
Both the economic and humanitarian situations are worsening.
The United Nations development agency says Afghanistan is teetering on the brink of "universal poverty'' which could become a reality in the middle of next year unless urgent efforts are made to bolster local communities and their economies.
It said the Taliban takeover of Afghanistan has put 20 years of steady economic gains at risk.
"Afghanistan pretty much faces universal poverty by the middle of next year,'' Kanni Wignaraja, UNDP's Asia-Pacific Director, told a news conference on Thursday. "That's where we're heading - it's 97-98% (poverty rate) no matter how you work these projections.''
Currently, the poverty rate is 72% and Wignaraja pointed to many development gains after the Taliban were ousted from power in 2001: Per capita income more than doubled in the last 20 years, life expectancy at birth was extended by about nine years, the number of years of schooling rose from six to 10, "and we got women into university.''
But she said Afghanistan now faces "a humanitarian and development disaster'' resulting from political instability, frozen foreign reserves, a collapsed public finance system, "a crush on local banking because of this,'' as well as the impact of the COVID-19 pandemic.
This year, the UN estimates, half of all children under five in Afghanistan will become acutely malnourished.
And after a severe drought, there are also water shortages - nine million Afghans now lack access to clean water.