US Special Representative Zalmay Khalilzad played a key role in pressing the Taliban to allow the departures, Reuters reported.
The departures were expected on Thursday September 9, and an exact breakdown of how many US citizens and people from other nations will be on the flight has not been shared.
The official could not say whether these Americans and third-country nationals were among people who have been stranded for days in Mazar-i-Sharif 260 miles north of Kabul on charter flights that were barred from taking off.
Planes chartered to carry people out of Afghanistan have been stuck at Mazar-i-Sharif International Airport, with some organizers saying the State Department was not doing enough to facilitate their departure.
The criticism came after an email leak suggested that the agency prevented several private flights from leaving Afghanistan with U.S. citizens and Afghan allies on board.
On Tuesday, US Secretary of State Antony Blinken had denied reports that the Taliban had blocked Americans attempting to fly out of a northern Afghan city. But he said that the militants had not allowed charter flights to depart because some people lacked valid travel documents.
Reports had said that 1000 people, including US citizens had been stuck at Mazar-i-Sharif airport for days awaiting clearance for their charter flights to leave.
Mr Blinken had said that Washington had identified a “relatively” small number of Americans seeking to depart from Mazar-i-Sharif. He added: “It’s my understanding is that the Taliban has not denied exit to anyone holding a valid document, but they have said those without valid documents, at this point, can’t leave.”
The US secretary of state also said: “Because all of these people are grouped together, that’s meant that flights have not been allowed to go.”