In a new letter to the European Union, a dozen Senate Republicans criticized the European bloc for its hesitance to designate Iran’s Islamic Revolutionary Guard Corps as a terrorist organization, arguing that the lack of action undermines efforts to counter both Iran and Russia.

“We write to express our disappointment in the European Union’s (EU) hesitation to designate the Islamic Revolutionary Guard Corps (IRGC) of Iran as an addition to the EU Terror List,” the lawmakers wrote in a letter sent on Wednesday to Josep Borrell, the EU high representative for foreign affairs and security policy. “Amidst the IRGC’s ongoing support of Russian war crimes in Ukraine, EU reluctance both weakens our collective resolve against Russia and ignores the Iranian government’s goal of sowing terror in the West.”

Lawmakers in the U.S., including both Sen. Jim Risch (R-ID) and Bob Menendez (D-NJ), the ranking member and chair of the Senate Foreign Relations Committee, have lamented that the EU and other European partners have been slow to adopt Washington’s more aggressive approach to Iran sanctions, especially following the collapse of nuclear talks. Risch led this week’s letter. The U.S., under the Trump administration, designated the IRGC as a terrorist group in 2019. 

Borrell has said that the EU lacks the authority to designate the IRGC, but the lawmakers note that the IRGC has been involved in attempted attacks in Europe. 

“The EU has made countless statements since the Russian invasion of Ukraine condemning violations of the laws of armed conflict, including a European Parliament resolution identifying Russia as a state sponsor of terrorism,” they continue. “The growing alignment of Russian and Iranian activities, including the use of Iranian drones in Ukraine, makes the IRGC complicit in Russia’s terror. An IRGC terror designation will sharpen and align the U.S. and EU responses to Russian aggression.”

Risch was joined on the letter by Sens. Lindsey Graham (R-SC), Marco Rubio (R-FL), Roger Wicker (R-MS), John Cornyn (R-TX), Pete Ricketts (R-NE), Bill Hagerty (R-TN), Ted Cruz (R-TX), Todd Young (R-IN), James Lankford (R-OK), Joni Ernst (R-IA) and Tim Scott (R-SC).