A member of Iran's Expediency Council died of coronavirus on Monday.
Mohammad Mirmohammadi, 71, was an Expediency Council member who advised Khamenei and settled disputes between him and parliament, reported Al Jazeera.
COVID-19 has already infected Iran's vice president and deputy health minister.
Mohammad has become the first top official infected with the disease which has affected members of the Islamic Republic's leadership, according to the official IRNA news agency.
The council advises Supreme Leader Ayatollah Ali Khamenei, as well as settles disputes between the supreme leader and parliament.
His death comes as other top officials have contracted the virus in Iran, which has the highest death toll in the world after China, the epicenter of the outbreak.