Mohammad Khatami, the former Iranian president, has attacked the "show trial" of dissidents in Tehran as unlawful and unconstitutional.
Mr Khatami's intervention came as the prosecution continued against more than 100 people, including a number of leading figures in the reform movement, over the violence which followed the country's disputed election results which gave victory to President Mahmoud Ahmedinejad.
It is the first such mass political prosecution since the 1979 Islamic revolution with dozens of senior officials, including former ministers, the vice-president and MPs, being tried. The defendants are charged with rioting, attacking military and government buildings, having links with armed opposition groups and conspiring against the ruling system. They face a maximum jail term of five years if convicted, unless they are charged with being a "mohareb", or enemy of God, which can carry the death penalty.
On his website, Mr Khatami, seen as a liberal in Iranian terms, said: "The trial on Saturday was a show and the confessions are invalid... What was called a trial was a violation of the constitution. Such show trials will directly harm the system and will further damage public trust. The most important problem with the trial procedure is that it was not held in an open session. The lawyers and the defendants were not informed of the contents of the cases ahead of the trial."
Mr Khatami, who served two terms as president before being succeeded by Mr Ahmadinejad in 2005, is viewed, because of his seniority, as a rallying figure for dissidents. The government has not, so far, taken any major punitive steps against him.
The defendants at the trial include former vice-president Mohammad Ali Abtahi, former deputy foreign minister Mohsen Aminzadeh, former MP Mohsen Mirdamadi, former deputy foreign minister Mohsen Aminzadeh, former government spokesman Abdollah Ramazanzadeh, former MP Mohsen Mirdamadi and former industry minister Behzad Nabavi.
State television has shown them in prison uniform with some in handcuffs. Some of those in the dock are also said to have bruising on their arms and faces. Some of those detained, including Mr Abtahi, were shown saying they had made mistaken statements and the votes had not, in fact, been rigged.
The former foreign service minister, a close Khatami aide, told the court he should not have taken part in protests: "I say to all my friends and all friends who hear us, that the issue of fraud in Iran was a lie and was brought up to create riots so Iran becomes like Afghanistan and Iraq and suffers damage and hardship."
Mr Abtahi also claimed that that defeated reformist presidential candidate Hossein Mousavi, Mr Khatami and former president Akbar Hashemi Rafsanjani had taken an "oath" before the vote to support each other.
"Mousavi probably did not know the country, but Khatami, with all due respect... knew all the issues. He was aware of the capability and power of the leader, but he joined Mousavi and this was a betrayal," Mr Abtahi said.
Mr Rafsanjani denied that any such deal was in place. Opposition figures have said the defendants had been under immense pressure to "confess their errors" since their arrest.Reuse content