The Taliban have reportedly prevented several planes intended to evacuate hundreds of people from leaving Afghanistan for days now, with a top Republican lawmaker describing it as a “hostage situation.”

The Associated Press reported Sunday that at least four planes have been prevented from taking off for unclear reasons. An Afghan official reportedly stated that the hundreds of passengers were all Afghans—saying that many did not have proper visas or passports. But some American lawmakers have said there are Americans among those attempting to evacuate.

“This is really, Chris, turning into a hostage situation, where they’re not going to allow American citizens to leave until they get full recognition from the United States of America,” Representative Michael McCaul, the top Republican on the House Foreign Affairs Committee, told Fox News Sunday host Chris Wallace on Sunday.

The Texas lawmaker said that hundreds of U.S. citizens were “left behind enemy lines” amid the chaotic American withdrawal from Afghanistan last month. McCaul blamed President Joe Biden, saying the commander-in-chief has “blood on his hands.”