Ayatollah Mohammadreza Mahdavi Kani, the head of Iran's most influential clerical body charged with choosing or dismissing the country's supreme leader, has died. He was 83.

Kani was the the chairman of the Assembly of Experts, a body of 86 senior clerics that monitors the supreme leader and picks a successor after his death, making it one of the most powerful institutions in Iran, though it doesn't involve itself in daily affairs of state.

Kani held the post since March 2011, after his predecessor, Iran's influential former President Akbar Hashemi Rafsanjani was forced out following a dispute with several hard-line clerics.

Kani, a former acting prime minister and interior minister in the 80s, had been in a coma since June. He was considered a moderate conservative.