Iran's supreme leader has appointed a new head to the country's powerful Revolutionary Guard, just after the U.S. designated the paramilitary force a terrorist group.

State-run Iranian media gave no reason for Ayatollah Ali Khamenei's decision to replace the Guard's commander.

Taking over will be Gen. Hossein Salami, a 59-year-old who had been serving as a deputy commander in the Guard.

He replaces Gen. Mohammad Ali Jafari, who had been in charge of the Guard for over 11 years.

The Revolutionary Guard is a separate force from Iran's standing military. It also oversees the country's ballistic missile program and runs its own intelligence operations.

Earlier this month, the Trump administration designated the Guard a terrorist organization. Iran responded by designating the U.S. military's Central Command as a terrorist organization.