Iranian opposition leader Mir Hossein Mousavi has called for the trial of those he claimed "committed fraud" in last year's presidential election.
He made the demand in a statement issued on the anniversary of violent protests that followed the vote.
Mr Mousavi also said the police and the military should stay out of politics. He demanded an independent judiciary.
Last week, he urged his supporters not to take to the streets to mark the anniversary to avoid bloodshed.
Scores of people were killed and thousands arrested during the violence that followed the controversial re-election of President Mahmoud Ahmadinejad on 12 June 2009.
"A fair trial of those who committed the election fraud, tortured and killed protesters must be held," Mr Mousavi said in the statement released on his website Kaleme.com.
Mr Mousavi also announced a "new charter" of policy aims for the opposition movement.
He called for an "end to the involvement of police and military forces in politics, the independence of the judiciary, and prosecution of those in plainclothes," referring to the Basij militia, deployed in Tehran last year during opposition protests against Mr Ahmadinejad.
He urged authorities to release political prisoners and to lift restrictions on political parties and social movements.
Last week, Mr Mousavi and his reformist ally Mehdi Karroubi called off mass protests planned for the one-year anniversary of President Ahmadinejad's re-election, saying they did not want to cause the loss of innocent lives.
Only sporadic demonstrations in Tehran and other Iranian cities were reported, amid a massive security presence and warnings from the intelligence ministry that protesters would be "charged as criminals" for "any illegal action and contact with the foreign media".
Mr Mousavi has repeatedly vowed to continue his struggle against the government, even saying he is not afraid to die for the cause of reform.