The Trump administration is considering executive actions that would designate Iran’s Revolutionary Guard and the Muslim Brotherhood, an influential movement across the Middle East, as terrorist organizations, people familiar with the discussions said.

A decision to target either of the two groups would mark a significant expansion of U.S. sanctions against Islamist organizations in the Middle East. They would join al Qaeda, Islamic State and dozens of other militant organizations currently on the U.S. terrorism list.

The White House is likely to move more quickly on the designation of the Islamic Revolutionary Guard Corps, which could be less of a challenge to implement, one person familiar with the discussions said. It was unclear when a decision would be made on either designation.

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White House Press Secretary Sean Spicer declined Wednesday to say whether the White House would take steps against either the Muslim Brotherhood or the IRGC. But, he said: “There’s no one that can question the president’s commitment to fully attacking and addressing the threat that we face by Islamic terrorists.”

The Revolutionary Guard is Iran’s elite military unit and reports directly to Supreme Leader Ayatollah Ali Khamenei, with a command separate from Iran’s traditional military. It was established following the 1979 Islamic revolution in Iran and over the past decade has also grown to dominate Iran’s economy, with holdings in property, oil and gas and telecommunications. U.S. officials estimate the IRGC controls as much as 50% of Iran’s economy.

Leaders of the Muslim Brotherhood, founded in Egypt in 1928, have said the group opposes political violence and wants to establish Islamic societies through democratic means. The U.S. designated its Palestinian offshoot, Hamas, a terror organization in 1997.