Iran's Supreme Leader warned government supporters against accusing opposition members of wrongdoing without proof, an indication that the Islamic government may be easing up on critics of the June presidential election.

Ayatollah Ali Khamenei, who has final say on all state matters in Iran, said while a suspect's own confession was admissible, his testimony or accusations could not be used against others not on trial for the unrest following President Mahmoud Ahmadinejad's re-election.

“We do not have the right to accuse without proof,” Khamenei said in a speech marking the end of the Muslim holy month of Ramadan in which he urged judiciary and security forces to pursue offenders within the bounds of the law. The speech was carried live on Iran's state radio and television.

“What a suspect says in court against a third party has no legitimate validity,” Khamenei said.

Khamenei did not single out any individuals, but his remarks appeared to refer to testimony by some detainees who claim that former President Hashemi Rafsanjani and other reformists supported opposition leader Mir Hossein Mousavi in the June 12 vote to weaken Khamenei.

He stressed that accusing others without any proof would create a climate of suspicion.

Reformists claim that widespread fraud handed incumbent President Mahmoud Ahmadinejad a win over Mousavi. Tens of thousands took to the streets in protest after the results, sparking a government crackdown in which hundreds were arrested or detained and dozens subsequently being brought to court in mass trials. Some opposition members say 72 died in the crackdown, roughly double the government's official casualty figures.

Since July, the street protests have largely died down, giving way to rifts between the country's clerics, with hardliners accusing Mousavi's reformist and moderate supporters of looking to destabilise the government and calling for their arrest.

Since the election, Khamenei has signaled that the government may ease up on the critics. His speech on the start of the Eid al-Fitr religious holiday appeared to be another push to stamp out tensions that have presented the country with its biggest internal political challenge since the 1979 Islamic Revolution.