Iran has warned supporters of the opposition movement to refrain from holding protests on Tuesday aimed at demanding the release of their leaders.
"Anyone who acts against the law will be dealt with," prosecutor general Gholam Hossein Mohseni Ejeie was quoted as saying Monday on the website of state television.
He was referring to calls by an opposition group for protests to take place on Tuesday.
Websites of opposition leaders Mir Hossein Mousavi and Mehdi Karroubi on Saturday posted calls for new protests to take on Tuesday in Tehran and other provincial cities to press for their release from house arrest.
The call was issued by the Coordination Council of the Green Path of Hope, an umbrella group backing the two leaders who steadfastly oppose President Mahmoud Ahmadinejad's government.
The group, which called previous protests on 14 February and 20 February , said that more demonstrations would be held on 15 March if Mousavi and Karroubi remained under house arrest beyond 1 March.
Officials have branded anyone who supports the two men as "anti-revolutionary," and on Monday Ejeie said the opposition movement had now transformed itself from "sedition to anti-revolution."
Mousavi and Karroubi led a string of protests in Iran after Ahmadinejad's controversial re-election in June 2009, which they claim was rigged.
Their opposition to Ahmadinejad has shaken the Islamic republic and divided the nation's elite Shia clergy.