Civil liberties groups are raising alarms about a bill making its way through Congress that applies pressure for a ban on travel to Iran for Americans using U.S. passports. The rights groups see the bill as part of a growing attempt to control the travel of American citizens and bar Iranian Americans in particular from maintaining connections with friends and loved ones inside Iran

“This bill is very concerning because it’s the beginning of a process of criminalizing something that is very normal for many people, which is traveling to Iran,” said Ryan Costello, policy director at the National Iranian American Council. “If you’re an American citizen, the government should not be controlling where you can travel.”

Among other provisions, the bill seeks to bar U.S. passport holders from traveling to Iran by rendering their passports invalid for such travel. Though the prohibition would need to be enacted by the State Department, the legislative proposal effectively encourages the move and, as with other sanctions against Iran, waiving the authority to enact the ban could incur political costs.