U.S. Secretary of State Antony Blinken on Wednesday called on the Taliban to allow charter flights carrying Americans and at-risk Afghans to depart from Afghanistan.

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.

Blinken said the United States was doing everything in its power to get the flights off the ground, but the Taliban was not permitting the flights to depart.

“We’ve made clear to all parties, we’ve made clear to the Taliban that these charters need to be able to depart,” Blinken said at a press conference in Germany.

(Reporting by Humeyra Pamuk, Daphne Psaledakis, Susan Heavey and Simon Lewis)