A senior opposition figure accused Iran's hardline judiciary and conservative lawmakers of being instruments in the intimidation of pro-reform activists and the trampling of constitutional rights.
The remarks by Mahdi Karroubi, who has often criticized Iran's leadership, were posted last night on his party's website.
They come three weeks ahead of the first anniversary of the disputed June 2009 election, which the opposition claims President Mahmoud Ahmadinejad won through massive vote fraud. The opposition says its leader, Mir Hossein Mousavi, was the rightful winner of the balloting.
"The judiciary, which ... is required under the constitution to defend constitutional freedoms of the citizens, has become an instrument in the hands of the ruling system and security and military agencies," Karroubi said, according to Sahamnews.org.
"Instead of providing security to the people, the judiciary has turned to intimidation and imprisonment," added Karroubi.
The opposition says at least 80 protesters have died so far in street clashes between security forces and protesters in the post-election turmoil. Authorities put the toll at about 30 in what has been Iran's worst unrest since the 1979 Islamic Revolution.
More than 120 people have been put on a mass trial since August on vaguely formulated charges that include seeking to topple the government through street protests. About a dozen have been sentenced to death, and more than 80 others received prison terms ranging from six months to 15 years.
Karroubi also lashed out at Ahmadinejad, saying his rule has set back the country and that the deteriorating economy has made life miserable for Iranians.
"The present head of government, with his strange behavior, has humiliated the Iranian nation," he said.
Karroubi said that the president's handing out of money to small countries in attempts to suggest their allegiance has been detrimental to Iran.
The opposition has called on supporters to mark the election anniversary with massive street protests. The government has warned it won't allow the rallies to take place, raising expectations of more violence.