Foreign companies that do business with Iran should be preparing to bolster their due diligence efforts as the U.S. pushes forward with the unprecedented move of designating the country’s Islamic Revolutionary Guard Corps as a Foreign Terrorist Organization.

After the designation takes effect April 15, providing support to the IRGC—a military unit that reportedly controls hundreds of companies in Iran’s energy, transportation, telecommunications, construction and metals and mining sectors—will be treated as a crime under the authority of the Antiterrorism and Effective Death Penalty Act of 1996.