Borrell said in January that the 27-member bloc cannot blacklist the IRGC as a terrorist group despite the European Parliament voting 598 to 9 in favor of a measure urging the designation. Following the vote, the E.U. Foreign Affairs Council decided to not execute the parliament’s recommendation, citing legal hurdles.

“It is something that cannot be decided without a court, a court decision first. You cannot say I consider you a terrorist because I don’t like you,” Borrell said at the time.

The Foreign Affairs Council is composed of the ministers of foreign affairs, defense and/or development of the member states.

While sympathizing with the legal complexities, the missive urges Borrell to “treat the issue with the utmost urgency,” given the threat posed by the IRGC. The letter cites a study from the Combating Terrorism Center at the United States Military Academy in West Point, New York, showing that in the past five years, the Revolutionary Guard Corps has instigated at least 33 plots against E.U. citizens.

“We believe that there is an abundance of evidence available to the E.U. to provide the necessary basis for a terror designation of the IRGC, particularly given the European Court of Justice’s ruling that investigations and prosecutions outside of the E.U. may be used as evidence to support additions to the terror list,” the letter states.

The United States listed the Revolutionary Guard Corps as a terrorist group under President Donald Trump, who did so after withdrawing from the 2015 Iran nuclear deal and imposing punishing sanctions on the regime in Tehran. Bahrain and Saudi Arabia designated the IRGC as a terrorist organization in 2018.