TENSIONS between the US and Iran have escalated after Donald Trump designated the country’s feared Revolutionary Guard Corps (IRGC) as a foreign terrorist organisation – the first time it has described a foreign government entity in such terms.

Iran immediately responded to the president’s ruling by labelling US Central Command as a terrorist group, according to the country’s state news service.

Relations between the two had cooled somewhat after Trump withdrew the US from the nuclear pact and this move is expected to further isolate Iran.

However, it could also have widespread implications for US personnel and policy in the Middle East and elsewhere.

The US has previously targeted some parts of the IRGC, most notably its elite Quds force.

In a statement yesterday, Trump said: “This unprecedented step, led by the Department of State, recognises the reality that Iran is not only a state sponsor of terrorism, but that the IRGC actively participates in, finances, and promotes terrorism as a tool of statecraft.”

He said the move was meant to “significantly expand the scope and scale” of pressure on Iran: “If you are doing business with the IRGC, you will be bankrolling terrorism.”

US Secretary of State Mike Pompeo said the measure would take effect in a week’s time. He said the US would continue to sanction and pressure Iran to “behave like a normal nation” and urged US allies to take similar action.

Pompeo said: “The leaders of Iran are not revolutionaries and people deserve better. They are opportunists.”

In a tweet, he added: “We must help the people of Iran get back their freedom.”

National Security Adviser John Bolton said labelling the IRGC as terrorists was “the rightful designation”.

Mohammad Javad Zarif, Iran’s foreign minister, seemed to anticipate the designation, with a tweet on Sunday aimed at Trump, saying he “should know better than to be conned into another US disaster”.

This is the Trump administration’s latest move to isolate Iran.

He withdrew from the Obama administration’s landmark nuclear deal with Iran in May 2018 and, in the months that followed, reimposed punishing sanctions, including those targeting its oil, shipping and banking sectors. The IRGC designation comes with sanctions, including freezes on assets it may have in US jurisdictions and a ban on Americans doing business with it or providing support for its activities.

Although it has broad control and influence over the Iranian economy, such penalties from the US may have limited impact.

The decision could, however, significantly complicate US military and diplomatic work, notably in Iraq, where many Shiite militias and Iraqi political parties have close ties to the IRGC, and in Lebanon, where the force has close ties to Hezbollah, which is part of the Lebanese government.