Mehdi Karroubi leads the National Trust Party Iranian opposition leader Mehdi Karroubi has been put under house arrest, his official website says.
Security officials at the premises say the measures will last until next week, it adds. No one is being allowed to enter the house except his wife.
Mr Karroubi and Mir-Hossein Mousavi, another opposition leader, had called for a rally on Monday to support the popular uprisings in Egypt and Tunisia.
The authorities refused permission, calling it a political move.
Although Iran’s establishment supports the Egyptian popular protests, a spokesman for Iran’s judiciary said on Wednesday that Iranians should show their solidarity by taking part in official rallies this Friday to commemorate the anniversary of Iran’s revolution.
Choosing another day to hold a rally means that the opposition leaders “wish to be in a separate front and will create divisions”, he told a news conference in Tehran.
Mr Karroubi, a 72-year-old cleric and former parliament speaker, ran against President Mahmoud Ahmadinejad during the disputed 2009 election which returned the hardline leader to power.
He currently leads the National Trust Party, and is seen as a political survivor who sought a soft and gradualist strategy of reforms.
His son, Hossein Karroubi, has told the BBC’s Mohsen Asgari in Tehran that even the opposition leader’s children and family members – with the exception of his wife – are not being allowed to see him.
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