The Trump administration has designated Iran’s Islamic Revolutionary Guard Corps as a foreign terrorist organization.

Why it matters: The Monday announcement, which marks the first time the U.S. has designated an element of a foreign government as a terrorist entity, is a further sign that the Trump administration will use any tool at its disposal to inflict pain on the Iranian regime. The pressure campaign has kicked into overdrive since President Trump pulled the U.S. out of the Iran nuclear deal last May.

Details: The move is designed to drain revenue from businesses in Europe and elsewhere controlled by the IRGC.

"This is a tool we’ve used over many many years to gain leverage over foreign terrorist organizations," one official said. "This designation has a lot of bipartisan support, historically."

Trump has long wanted to make this designation. Senior administration officials told reporters Monday that the announcement comes after months of interagency deliberation "where everyone’s ideas were able to be heard," and that ultimately the final decision was made at the president's request.

What's next: Officials said the administration is calling on other nations to isolate the IRGC, stating that "many countries will face a pretty clear choice here."

"It's no secret that Europe and the U.S. don’t exactly see eye to eye on the JCPOA [Joint Comprehensive Plan of Action, or the Iran nuclear deal]," one official said. "However, we do have a shared interest. … We should all be able to agree that the world leader of state-sponsored terrorism should not be able to use European soil as fertile ground for its terrorist operations."

The backdrop: The Wall Street Journal first reported the expected move last week, noting that national security adviser John Bolton and Secretary of State Mike Pompeo have been "strong proponents of the move," according to U.S. officials.

However Pentagon officials, including chairman of the Joint Chiefs of Staff Gen. Joe Dunford, have "cautioned against the move ... fearing it could lead to a backlash against U.S. forces in the region without inflicting the intended damage to the Iranian economy," per the WSJ.

Update: Shortly after the president's announcement, Iran’s Supreme National Security Council said it designated the U.S. Central Command, CENTCOM, and its forces as terrorist groups and labeled the U.S. a “supporter of terrorism,” per the AP.