The website of Iranian opposition leader Mehdi Karroubi says the country's security forces have arrested one of his sons and tried to arrest a second son.
According to a Tuesday report on the website sahamnews.org, the security forces entered Ali Karroubi's home late Monday and arrested him along with his wife, who was later released.
The website also says security forces entered Hossein Karroubi's home but "failed" to arrest him because he was not there.
The opposition site says security forces also entered Mehdi Karroubi's home late Monday and seized "books and documents."
Iranian authorities had previously placed Mehdi Karroubi and fellow opposition figure Mir Hossein Mousavi under house arrest. The two are leaders of the "Green Movement," which staged a rally in Tehran on February 14, the largest by the opposition in more than a year.
Green Movement demonstrators turned out for new protests Sunday but Iranian security forces hampered their efforts to hold rallies.
Karroubi and Mousavi led large-scale protests in 2009 after losing the presidential election to President Mahmoud Ahmadinejad in a vote they say was rigged. Forces loyal to Iran's government crushed those demonstrations.
Some information for this report was provided by AP, AFP and Reuters.