It's an unprecedented move because the US has never before used the designation for an entire foreign government entity.
USA officials said the terrorist label, which takes effect on April 15, would make it a criminal offense in the United States to provide "material support" to the Revolutionary Guards, with violators subject to up to 20 years in prison.
Furthermore, much of the turmoil we see around the world is a direct result of the actions of the IRGC and state sponsorship of terrorism by Iran.
The Guards were formed after the 1979 Islamic revolution with a mission to protect the regime, as opposed to more traditional military units that defend borders. It may make the administration look tough to its political supporters, but it doesn't inflict further economic harm on Iran or extend the reach of a harsh sanctions regime that has already caused great hardship for the Iranian people.
In a statement, Foreign Ministry spokesman Bahram Qassemi said Zarif's request was based on the law to deal with USA human rights violations and provocative and terrorist acts in the region, ISNA reported.
The president added that the move was meant to "significantly expand the scope and scale" of pressure on Iran.
The designation imposes sanctions that include freezes on assets the Islamic Revolutionary Guard Corps may have in USA jurisdictions and a ban on Americans doing business with it.
Some influential members of Congress expressed their support for Trump's decision on Monday. According to the WSJ, the announcement could be made as early as Monday, and would be the first branding of a sovereign country's military as a terrorist group. Ben Sasse, Nebraska Republican, said.
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During a press conference at the State Department, Secretary of State Mike Pompeo said the decision comes in response to the country's ongoing sponsorship of terrorist groups. "This would greatly expand our ability to roll back Iran's ability to fund and export terror overseas".
The U.S. made the designation Monday to increase global pressure on Iran. "They behave like a terrorist organization and will now be treated accordingly".
The IRGC designation is seen as the latest in a series of steps Mr. Trump has taken to boost Mr. Netanyahu's fortunes, including USA recognition of Israeli sovereignty over the Golan Heights.
Netanyahu took to Twitter to thank his "dear friend" Trump for answering "another important request that serves the interests of our country and the region". "We will continue to act together in any way against the Iranian regime that threatens the state of Israel, the United States and the peace of the world".
The information the USA government has on their illicit activities is clear: Iran is the largest exporter of terrorism in the world.
Tehran responded in kind, announcing a couple of hours later that its top security council has designated the United States a "state sponsor of terrorism" and US forces in the region "terrorist groups".
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The US claims that the Revolutionary Guards' presence in Syria - where it helps support the armed forces of the Syrian government - is a direct threat to Israel.
The US and its regional allies such as Saudi Arabia and Israel accuse Iran of trying to destabilise the region in part by using IRGC and its affiliated Quds force, which played a pivotal role to defeat Daesh in Iraq.