As expected, the US State Department on Monday announced that it will designate Iran’s Islamic Revolutionary Guard Corps (IRGC) a foreign terrorist organization. The IRGC is a military branch created after the 1979 Iranian Revolution with the aim of defending the country’s theocratic system. This will be the first time that the US adds a foreign government entity to its list of foreign terror groups.

While Israel and Saudi-Arabia supported the US move, Iran slammed it as “illegal and dangerous” and warned that the US “will be responsible for dangerous consequences of this adventurist measure.” In addition, Iran in turn designated the US government a sponsor of terrorism and part of the US military a terrorist organization.

Analysts warn that the US decision will complicate US relations with Iraq, Lebanon and other countries with links to the IRGC. Furthermore, Trita Parsi, the president of the National Iranian American Council, stated that while the move “will not put any significant additional economic pressures on Iran,” it will “close yet another potential door for peacefully resolving tensions with Iran. Once all doors are closed, and diplomacy is rendered impossible, war will essentially become inevitable.”

Read more: Iran Warns U.S. Of ‘Dangerous Consequences’ As Saudi Arabia And Israel Back U.S. Move