TEHRAN: Former President Akbar Hashemi Rafsanjani lost his position on Tuesday as the head of a powerful clerical body charged with choosing or dismissing Iran's supreme leader. Rafsanjani is a bitter enemy of President Mahmoud Ahmadinejad, and tacitly supported his rival, Mir Hossein Mousavi, in Iran's bitter dispute over the 2009 presidential elections. Supporters of Ahmadinejad had lobbied hard in recent weeks to push Rafsanjani out of the post and supported Ayatollah Mohammad Reza Mahdavi Kani to replace him as the head of the Assembly of Experts. Kani is a moderate conservative not seen as a supporter of the opposition. The Experts Assembly monitors the all-powerful supreme leader and picks a successor after his death. That makes it potentially one of the most powerful institutions in Iran, although it does not involve itself the daily affairs of state. Rafsanjani told the assembly that he wouldn't seek re-election to “avoid division” if Kani ran for the post, and Kani got 63 votes as the sole candidate for the post. Rafsanjani, who had chaired the assembly since 2007, will remain a member of the 86-member assembly. The 77-year-old Rafsanjani — who served as president from 1989-1997 — still heads the powerful Expediency Council — a body arbitrating between legislators and the Guardian Council, the hard-line constitutional watchdog that approves candidates for parliament, president and the Assembly. Rafsanjani has long been an elusive inside player in Iran's clerical leadership. He has supported a policy of improving relations with the West including the United States and has tried to play a bridging role between hardline extremists and the marginalized reformist opposition. But Rafsanjani has been losing power gradually over the years step by step. His son, Mohsen, resigned as the head of Tehran subway system after 17 years in office on Friday, citing lack of support from the government. Mohsen Hashemi said Ahmadinejad's government had ulterior political motives in withholding a $2 billion budget for the subway system that was approved by parliament. Rafsanjani's daughter, Faezeh, who has appeared at opposition protests in the past, was briefly detained last month while allegedly trying to cause unrest by chanting anti-government slogans in one of the main streets of Tehran. Protesters tear-gassed Iranian security forces fired tear gas at anti-government protesters as they tried to hold a demonstration in Tehran Tuesday, the opposition website Kaleme.com reported. “Security forces blocked the roads to Enghelab (Revolution) Square (in central Tehran) and fired tear gas at people several times as they tried to stage anti-government demonstrations,” the website said. Kalame.com reported “heavy security force deployments in several of Tehran's main squares.” Foreign media have been banned from on-the-spot reporting of any unauthorized gatherings. The reports of the demonstration came after Kaleme.com said that opposition leader Mir Hossein Mousavi and his wife Zahra Rahnavard were at their home and not in jail as it had previously reported.