MOSCOW, June 22 (RIA Novosti) - Political tensions in Iran are rising, with senior figures in the Islamic Republic considering whether to depose Supreme Leader Ayatollah Ali Khamenei, an Arabic-language TV channel said.

Tehran has seen mass demonstrations over alleged ballot fraud in the landslide reelection of hardline President Mahmoud Ahmadinejad on June 12. Official results gave the incumbent 63% of the vote, with reformist challenger Mir Hossein Mousavi getting 34%.

Khamenei said during Friday prayers that the margin of victory was too great for the election to have been stolen, and declared his support for Ahmadinejad.

Dubai-based Al-Arabiya TV channel said former Iranian President Akbar Hashemi Rafsanjani becomes a key figure in any move to depose Khamenei.

Rafsanjani heads two influential organizations - the Expediency Council, which is a mediator between parliament and the Council of Guardians, and the Assembly of Experts, which has the power to remove the country's supreme leader.

The Al-Arabiya website cites a high-ranking source in the city of Qom, who said Rafsanjani, the Assembly of Experts and the Council of Guardians have agreed to depose Khamenei but do not intend to appoint a successor for the time being, mulling the establishment of a collective supreme rule.

Rafsanjani has been reported to have secured the support of Ayatollah Ali al-Sistani, one of the most influential Shiite leaders.

Should Khamenei be deposed, Ahmadinejad will be dismissed.

The Assembly of Experts consists of 86 Islamic scholars, elected by the public for 8 years, with candidates first approved by the Council of Guardians.

Rafsanjani has not made any public announcements since the elections. Shortly before the vote, he had a conflict with the president, who accused him of corruption, and demanded that the supreme leader involve himself, but Khamenei merely condemned Ahmadinejad's words.

Faezeh Rafsanjani, an elder daughter of the expert assembly head, supports Mousavi, whom her father also supports. She and four other relatives of Rafsanjani were arrested during a Tehran demonstration Saturday. On Sunday they were released.

At least 457 people were arrested during rioting in Iran's capital on Saturday as protests continued against the country's disputed presidential election, Mehr news agency reported on Monday.

At least 13 protesters were killed and 20 wounded on Saturday, Press TV said, citing local officials. Meanwhile, some hospital sources said 19 people had died as a result of clashes with police.