The Trump administration on Monday designated the Iranian Revolution Guards Corps (IRGC) as a foreign terrorist organization, taking an unprecedented step that seems to increase pressure on Tehran.

The move seems certain to bring a new level of tension between the two countries, as Iran’s leaders have said they will retaliate in kind.

Iranian lawmakers on Sunday prepared legislation that would label the U.S. military as a terrorist group, according to IRNA.

President Trump announced the designation on Monday, in a shift from the decades in which the U.S. has accused Iran of being a state sponsor of terrorism.

With the designation, anyone who deals with the IRGC could run the risk of facing criminal charges.

It’s the first time the U.S. has declared an element of a foreign government to be a terrorist organization, the Trump administration says.

On Sunday, Major General Mohammad Ali Jafari, the commander of the IRGC, warned that if the U.S. labels his force as terrorist, the result would mean the IRGC could target the U.S. military the same way it currently targets ISIS.

In recent months, the Trump administration has sought to impose “maximum pressure” on Iran, after abandoning the nuclear deal brokered during the Obama administration. Even before news emerged of a possible terrorism designation for the IRGC, more than 970 Iranian entities and individuals were already under U.S. sanctions.

SP/PA