AA/Sputnik WASHINGTON/Tehran - In a tit-for-tat move the US and Iran on Monday labelled each other’s militaries as terrorist groups.

The Trump administration took the unprecedented action of designating Iran’s Islamic Revolutionary Guards Corps (IRGC) a “foreign terrorist organisation.”

The move marks the first time a government agency has been blacklisted as a terrorist body, though parts of the corps had previously been designated, namely its elite external operations wing, the Quds Force.

In response, Iran’s Supreme National Security Council declared that it has designated the United States Central Command, also known as CENTCOM, and all its forces as terrorist and labelled the US as a “supporter of terrorism.”

The semi-official Fars news agency reported the statement by Iran’s National Security Council on Monday.

The statement from the council came after Iran’s foreign minister said he wants to include the Middle East-based US military forces on his country’s “terrorist groups” list.

Trump designates Iran Guards ‘terrorist group’ s Tehran responds by branding Centcom terrorist group s Also declares US as state ‘supporter of terrorism’

Earlier, US President Donald Trump had long been mulling the penalty, but the process to designate the Iran’s corps gained traction in the past few months as his administration seeks to escalate pressure on Tehran.

Trump said the designation “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.”

The designation “makes crystal clear the risks of conducting business with, or providing support to, the IRGC. If you are doing business with the IRGC, you will be bankrolling terrorism,” the president said in a statement.

It will take full effect seven days after Monday’s announcement, according to the State Department’s counterterrorism coordinator, Nathan Sales.

Shortly after the formal rollout, Iranian Foreign Minister Javad Zarif sent a letter to Iranian President Hassan Rouhani and Iran’s Supreme National Security Council urging Tehran to designate US Central Command, which is responsible for US forces in the Middle East, as a terrorist organisation, according to Iranian media.

Trita Parsi, the president of the National Iranian American Council, doubted whether the new action would increase economic pressure on Tehran, warning it instead “closes 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. This is hardly a coincidence as the elements who have pushed for this dangerous decision have a long and public track record of pushing the US towards war with Iran,” Parsi added in emailed remarks to Anadolu Agency.

The IRGC has sprawling business interests across the Iranian economy, and was created to be the vanguard of Iran’s 1979 revolution. It operates more autonomously than the rest of the Iranian military, answering only to Iran’s supreme leader.

It alone controls Iran’s ballistic missile forces. Monday’s action opens the door for criminal prosecutions of individuals who do business with the corps, and could allow the US to deny US entry to such individuals.

The designation could hinder US diplomacy, particularly in Iraq and Lebanon where officials regularly have contacts with the corps and its representatives.

According to Irna, the US Central Command is responsible for defending and promoting US interests in 20 nations in the Middle East, Central and South Asia, and the strategic waterways that surround them.

Zarif in its letter to the Iraninan council referred to the US military forces’ covert and open support for the terrorist groups in the region and their direct interference in terror activities and offered the Supreme National Security Council to enlist CENTCOM in its terror list according to the Iranian parliament’s ‘Bill Against US Adventurist and Terrorist Activities in the Region”.

Responding, a vast majority of lawmakers in Iran’s parliament issued a statement threatening to designate elements of the US military a terror group.