Iran's supreme leader will deliver a Friday sermon in Tehran for the first time since 2012, as the Islamic Republic grapples with the fallout from the targeted killing of its top general in a U.S. airstrike and popular anger at its accidental shootdown of a passenger plane.

Iran deployed riot police in the capital on Sunday expecting more protests after its Revolutionary Guard admitted to accidentally shooting down a passenger plane at a time of soaring tensions with the United States.

The Western allegation that Iran shot down a Ukrainian jetliner and killed 176 people offers a grim echo for the Islamic Republic, which found itself the victim of an accidental shootdown by American forces over 30 years ago.