The Imam Khomeini Institute for Education and Research, led by Mesbah Yazdi, said he had been hospitalized in recent days with a digestive illness.
The prominent cleric played a major role in the 1979 uprising that overthrew Western-backed Iranian shah Mohammed Reza Pahlavi, according to the Iranian publication Press TV.
Mesbah Yazdi was seen as a tough and anti-Westerner in general, including occupying anti-US positions. An open critic of the liberal press, she was known to have ratified repressions against the internal 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 Mehr news agency said Mesbah Yazdi is close to the country’s top leader, Ayatollah 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 of the Cultural Revolution, Press TV reported.