The United States will designate Iran's Revolutionary Guards as a terrorist organization, an unprecedented move that would ramp up pressure on the elite force, The Wall Street Journal reported Friday.

The newspaper, quoting unnamed officials, said President Donald Trump's administration would announce the long-mulled decision as soon as Monday and that concerned defense officials were bracing for the impact.

The Islamic Revolutionary Guards Corp was formed after the 1979 Islamic revolution with a mission to defend the clerical regime, in contrast to more traditional military units that protect borders.

The Revolutionary Guards have amassed strong power within Iran, including with significant economic interests.

The Guards' prized unit is the Quds Force, named for the Arabic word for Jerusalem, which supports forces allied with Iran around the region including Syrian President Bashar al-Assad and Lebanon's Hezbollah.

The Trump administration has already imposed sweeping sanctions on Iran after withdrawing last year from an international agreement under which Tehran drastically scaled back its nuclear program.

A foreign terrorist designation would make any activities of the group toxic for the United States, with any transactions involving US institutions or individuals subject to punishment.

The Wall Street Journal said that the Pentagon and the CIA had reservations about the move, saying it would increase risks for US troops without doing much more to damage the Iranian economy.

Pentagon increases number of U.S. troops killed by Iran in Iraq to 603
Washington DC (UPI) Apr 05, 2019 –

The Pentagon has revised the estimate on the number of U.S. troops in Iraq killed by Iranian-backed militias to 603, from roughly 500, between 2003 and 2011.

During a State Department briefing Tuesday, Special Representative for Iran Brian Hook said the revised figures are taken from recently declassified U.S. military documents. The original estimate came from Chairman of the Joint Chiefs of Staff General Joseph Dunford in 2015.

"We were not always able to attribute the casualties that we had to Iranian activity, although many times we suspected it was Iranian activity, even though we did not necessarily have the forensics to support that," Dunford told Congress during a confirmation hearing.

Islamic Revolutionary Guard Corps, which is Iran's elite military force that protects the regime from internal and external threats, is responsible for 17 percent of all U.S. service personnel deaths in Iraq. Iran supplied weaponry to Shiite militias fighting U.S. occupation.

"These casualties were the result of explosively formed penetrators, other improvised explosive devices, improvised rocket-assisted munitions, rockets, mortars, rocket-propelled grenades, small-arms, sniper, and other attacks in Iraq," Navy Cmdr. Sean Robertson, a Pentagon spokesman, told Military Times.

In addition, "thousands" of Iraqi troops and civilians were killed in attacks by Iranian proxy forces, according to Hook.

Most deaths occurred during the U.S. surge in Iraq, the Pentagon. President George W. Bush added 20,000 more troops into the country, mainly Baghdad, in January 2017.

Hook told reporters the United States continues to pressure Iran with sanctions.

"We are imposing costs on the regime for behaving as an outlaw expansionist regime," he said. "The regime is weaker today than when we took office two years ago. Its proxies are also weaker. Unless the regime demonstrates a change in policy and behavior, the financial challenges facing Tehran will mount."