The State Department reissued a travel warning Monday that emphasized the risks facing U.S. citizens in Iran.

“Iranian authorities continue to unjustly detain and imprison U.S. citizens, particularly Iranian-Americans, including students, journalists, business travelers, and academics, on charges including espionage and posing a threat to national security,” the warning reads. “U.S. citizens traveling to Iran should very carefully weigh the risks of travel and consider postponing their travel.”