Iran's Assembly of Experts has chosen hard-liner Ayatollah Ahmad Jannati to the powerful body, which is responsible for electing and overseeing the work of Iran's Supreme Leader Ayatollah Ali Khamenei.
The 76-year-old Khamenei, who has the final say on all state policies in the Islamic republic, underwent prostate surgery in 2014 amid rumors that he is in frail health.
The 88-member Assembly of Experts elected Jannati with 51 votes after its inauguration on May 24.
Two other conservatives, Ayatollah Ebrahim Amini and Mahmud Hashemi Sharhoudi, won 21 and 13 votes, respectively.
No moderates or reformists stood for the post.
Jannati secured reelection in a February vote that saw a landslide for reformist and moderates in Tehran and big gains for them elsewhere.
Among the candidates who were elected to the Assembly of Experts in Tehran, Jannati finished with the least support. The assembly remains controlled by conservatives.
Jannati, an 89-year-old cleric, also heads the Guardians Council -- the unelected constitutional watchdog that disqualified hundreds of reformist candidates from the parliamentary and assembly elections.
Under Jannati’s watch, some 3,000 candidates were barred from running in Iran's February elections for the parliament. They included moderates and reformists.
"Under the shadow of [Supreme Leader Ayatollah Khamenei], we hope to act in such a way that both God and the leader are satisfied with us," Jannati was quoted as saying by the hard-line Fars News Agency after his election.
Jannati also emphasized comments by Khamenei that the assembly should remain committed to the ideals of Iran's 1979 revolution.
Jannati is a critic of President Hassan Rohani and Rohani's attempts to end Iran's isolation by normalizing relations with the West.
Rohani and his ally, former President Akbar Hashemi Rafsanjani, also are members of the Assembly of Experts. Rafsanjani is a rival of Khamenei.
Rafsanjani did not stand as a candidate in the voting.
With reporting by AFP, Reuters, IRNA and Fars