Iranian Police Clash with Protesters
Thousands of opposition supporters have clashed with security forces in the centre of the Iranian capital, Tehran.
Police used tear gas and detained dozens rallying in solidarity with uprisings in Egypt and Tunisia. There was one report of a death in Tehran.
The BBC also received reports of similar protests being held in the cities of Isfahan, Mashhad and Shiraz.
Earlier, the police placed opposition leader Mir Hossein Mousavi under house arrest, according to his website.
It said the move was intended to prevent the former prime minister attending the march in Tehran, which the authorities had prohibited. The road leading to Mr Mousavi's house was also blocked by police vans.
Fellow opposition leader Mehdi Karroubi, a former speaker of parliament and a senior cleric, is also reportedly under de facto house arrest.
Both men disputed the re-election of President Mahmoud Ahmadinejad in June 2009, which triggered mass protests that drew the largest crowds in Iran since the Islamic Revolution in 1979. The demonstrations eventually led to a brutal crackdown.
The opposition says more than 80 of its supporters were killed over the following six months, a figure the government disputes. Several have been sentenced to death, and dozens jailed.
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