TEHRAN

Iran said Tuesday U.S. sanctions on Supreme Leader Ayatollah Ali Khamenei shut "the doors of diplomacy" between Tehran and Washington, according to the official IRNA news agency.

"The useless sanctioning of Islamic Revolution Supreme Leader, and the commander of Iranian diplomacy means closing the doors of diplomacy by the U.S. desperate administration," Foreign Ministry spokesman Abbas Mousavi said on Twitter.

"Trump's government is annihilating all the established international mechanisms for keeping peace and security in the world," he said.

On Monday, the Donald Trump administration imposed sanctions on Khamenei, his office and eight senior leaders of Iran's elite Islamic Revolutionary Guard Corps (IRGC), including the commanders of its air force and ground forces, and five naval district leaders.

The sanctions on Khamenei and his office are set to "lock up" billions of dollars worth of assets, U.S. Treasury Secretary Steven Mnuchin told reporters.

Trump has instructed that Iranian Foreign Minister Javad Zarif be sanctioned later this week, Mnuchin said.

Tensions have been rising between the U.S. and Iran since May 2018, when Washington unilaterally withdrew from a landmark 2015 nuclear deal between Tehran and the five permanent members of the UN Security Council plus Germany and the EU.

The U.S. has since embarked upon a diplomatic and economic campaign to put pressure on Iran in order to renegotiate the agreement, as well as other Iranian activities Washington considers to be "destabilizing".

As part of its campaign, the U.S. has reimposed sanctions on exports of Iranian crude oil, which have nosedived the Iranian economy.