The Imam Khomeini Educational and Research Institute, which Mesbah Yazdi headed, said he had been hospitalized over the past few days with a disease to his digestive system.
Mesbah Yazdi was seen as a hardliner and anti-West in general, including holding anti-US positions. An outspoken critic of a liberal press, he was known to have ratified crackdowns on domestic opposition, feminism and gender equality.
Iranian President Hassan Rouhani offered condolences on Mesbah Yazdi’s passing, according to Press TV, which reported Mesbah Yazdi was 85 years old.
Iran’s semi-official Mehr news agency said Mesbah Yazdi was close to the country’s Supreme Leader Ayatollah Ali Khamenei.