Iranian opposition leader Mir Hossein Mousavi has called for a referendum on what he calls the "destructive" policies of President Mahmoud Ahmadinejad.
In a message posted Tuesday on his website Kaleme.com Mousavi accuses Mr. Ahmadinejad of isolating Iran in the world and harming the Iranian economy through "adventurism and dictatorship."
Mousavi is a prominent reformist who ran against Mr. Ahmadinejad in a disputed 2009 election that gave the conservative president a second term. The opposition leader says he was the rightful winner but was denied victory through fraud.
In his latest criticism of Mr. Ahmadinejad, Mousavi appeared to be referring in part to a speech the president gave to the U.N. General Assembly in New York last month.
In the address, Mr. Ahmadinejad suggested the U.S. government staged the September 11, 2001 terrorist attacks on the United States, prompting a walkout by the U.S. and other Western delegations.
Iran's oil-based economy is under strain from international sanctions aimed at pressuring Tehran to stop sensitive nuclear activities. Western nations accuse Iran of trying to develop nuclear weapons under cover of a civilian energy program, a charge Tehran denies.
Hundreds of thousands of Iranian reformists protested Mr. Ahmadinejad's re-election, triggering a government crackdown that opposition activists say killed 72 people. Iranian authorities also arrested hundreds of people and sentenced more than 80 of them to prison.
The Iranian government says the post-election unrest killed about 30 people, including security personnel. It accuses opposition leaders of being part of a foreign plot to undermine the country's Islamic establishment.
In a sign the crackdown is continuing, Iranian security forces raided Mousavi's office last month.
Some information for this report was provided by AP, AFP and Reuters.