After President Joe Biden’s withdrawal of all U.S. troops by Aug. 31, the U.S. will continue to help U.S. citizens and residents and Afghans who worked with Americans or are otherwise at risk from the Taliban get out of the country, according to Secretary of State Antony Blinken.

But it’s unclear how that will be possible after the U.S. cedes control of the airport to the Taliban and ends evacuation flights — and it will mean leaving thousands of Afghans that the administration had previously said they would help behind.

Biden and Blinken have each said that the U.S. is “on track to complete our mission” before that Aug. 31 deadline, without specifying what the administration considers the scope of that mission — including how many Afghans they will evacuate.

In contrast, Blinken detailed how many Americans the U.S. has evacuated — some 4,500 to date — and how many the administration believes are left behind — 500 with whom the State Department has made contact with and up to 1,000 more who registered with the embassy.

“Let me be crystal clear about this — there is no deadline on our work to help any remaining American citizens who decide they want to leave to do so, along with the many Afghans who have stood by us over these many years and want to leave and have been unable to do so. That effort will continue every day past Aug. 31st,” Blinken told reporters Wednesday.

But starting on Sept. 1, that effort will rely on the Taliban, whose spokesperson said Tuesday they will not let Afghans leave the country.

In contrast, Blinken said, “The Taliban have made public and private commitments to provide and permit safe passage for Americans, for third-country nationals and Afghans at risk going forward past Aug. 31st” and to keep Kabul’s international airport running.

He added the U.S., backed by international allies, will hold them to it, without specifying how beyond using “every diplomatic, economic, political and assistance tool at my disposal (and) working closely with allies and partners who feel very much the same way.”

The U.S. is in discussions already with the international community on how to keep the airport open, according to American officials, including countries like Qatar and Turkey that have closer ties to the Taliban.

Blinken didn’t detail what levers the U.S. could use to hold the Taliban to its promises, but he did say that if it let “people who want to leave Afghanistan” leave, upheld basic rights and prevented its territory from becoming a launching pad for terror attacks, “that’s a government we can work with.”

Pressed on whether the administration was abandoning Afghan allies, including interpreters or translators who weren’t far enough along in the special immigrant visa process, a senior State Department official told ABC News, “We have always said that we are committed to bringing out Americans who wish to be repatriated. We are going to do as much as we can for as many people as we can beyond that.”

But while the administration never specified how many Afghans that applied to, it has said repeatedly it would help those who served the U.S. military and diplomatic missions over the last 20 years.

“Our message to those women and men is clear — there is a home for you in the United States if you so choose, and we will stand with you just as you stood with us,” Biden said on July 8, before the Taliban surprised the administration with the speed with which it took over Afghanistan.

The senior State Department official said that “commitment we have to individuals who may be at risk” has to be weighed against “the safety and security of our diplomats, of our service members, of others who are involved in this operation.” Biden, Blinken and other officials have said the threat from the Islamic State group’s affiliate in Afghanistan remains high, putting U.S. military and diplomatic personnel in danger.

“We’re operating in a hostile environment in a city and country now controlled by the Taliban, with the very real possibility of an ISIS-K attack. We’re taking every precaution, but this is very high-risk,” Blinken said Wednesday.

While the U.S. has been unclear about which Afghan interpreters will be evacuated, Blinken was more explicit about pledging to help those who worked at the U.S. Embassy in Kabul. Several staffers have been blocked by Taliban fighters from approaching the Kabul airport and getting their seats on evacuation flights.

“Along with American citizens, nothing is more important to me as secretary of state than to do right by the people who have been working side-by-side with American diplomats in our embassy,” Blinken said. “We are relentlessly focused on getting the locally-employed staff out of Afghanistan and out of harm’s way, and let me leave it at that for now.”