Decree comes after hardline backers of the Iranian government accused officials of treason for signing an MoU with US.

Hardline factions in Iran believe that instead of avenging the late supreme leader’s killing, Iranian officials have surrendered by signing an agreement with the US.

Iran's supreme leader, Mojtaba Khamenei, warned of “unforgettable lessons” if the U.S. continues its attacks in a statement read on state television.