Blinken's testimony came two weeks after the completion of the Afghanistan withdrawal.
"So as of the end of last week, we had about 100 hundred American citizens in Afghanistan who told us that they wish to leave the country. And I want to emphasize that this is a snapshot in time. It's more accurately a moving picture, as you know, stepping back for a minute to know precisely at any given moment of time exactly how many American citizens are in any country," Blinken told the House Foreign Affairs Committee.
"It's something we can't and don't know. Americans are not required to register when they go to a foreign country or if they reside there. And so from the start of this effort, we've been engaged in an intense effort to identify every American citizen that we could in Afghanistan, to be in touch with them, in contact with them and to work with them if they wanted to leave," Blinken continued.
The secretary of state also acknowledged that charter flights in Afghanistan are still being prevented from leaving. "There have been charter flights that have been there for some time, that have not been allowed to leave," Blinken said.
Blinken's admission sparked fierce criticism from Republicans.
"Secretary Blinken just acknowledged the Taliban has blocked charter flights out of Afghanistan, with Americans still there trying to get out. We’re in a hostage crisis. And today Joe Biden is campaigning in California," former White House chief of staff Mark Meadows wrote on Twitter.
While Blinken faced aggressive questions from Republicans, Democrats on the committee largely rushed to defend the Biden administration from criticism.