The Imam Khomeini Institute of Education and Research, headed by Mesbah Yazdi, said he had been hospitalized in recent days with a disease of the digestive system.
The prominent cleric played an important role in the 1979 uprising that overthrew the Western-backed Shah of Iran, Mohammed Reza Pahlavi, according to Iranian state TV Press.
Mesbah Yazdi was seen as hard-line and anti-West in general, including anti-US positions. A outspoken critic of the liberal press, he was known to have ratified repressions against domestic opposition, feminism and gender equality.
According to regional experts, he was a spiritual mentor to Mahmoud Ahmadinejad, the former Iranian president who served from 2005 to 2013.
Iranian President Hassan Rouhani offered condolences on the death of Mesbah Yazdi, according to Press TV, which reported that Mesbah Yazdi was 85 years old.
Iran’s semi-official news agency Mehr said Mesbah Yazdi was close to supreme Ayatollah leader Ali Khamenei.
Mesbah Yazdi was a member of the Assembly of Experts – the body responsible for electing and monitoring the performance of Iran’s Supreme Leader – and the Supreme Council for the Cultural Revolution, Press TV reported.