Iranian opposition leader Mir-Hossein Moussavi on Sunday accused authorities of torturing detained activists to get confessions, his website reported, according to dpa. "The torturers and confession-makers have brought the issue to a point where their victims are among those who have remarkably served this country and the system," Moussavi said in a statement posted on his website, Ghalam News, on Sunday. The first session of trials of about 100 demonstrators, political activists and journalists, who were arrested during the post-election unrest, began on Saturday in Tehran. A variety of charges had been filed against defendants. All stand accused of acting against national security by pushing for a "Velvet Revolution," a reference to the bloodless revolt that forced the collapse of the Communist regime in then Czechoslovakia in 1989. Moussavi rejected the charges and said: "People are seeking freedom and justice." He added that their actions were not tied to events abroad. Prominent activists and former officials who were in office during the reformist Mohammad Khatami's eight-year presidency - including former vice-president Mohammad-Ali Abtahi, former government spokesman Abdollah Ramezanzadeh and former deputy foreign minister Mohsen Aminzadeh - were among the accused appearing in the courtroom. Iranian authorities blamed Western countries, particularly the United States and Britain, for fueling the recent unrests aiming at toppling Islamic establishment in Iran. Those countries have denied the claim. "The scenes which we saw were nothing but an awkward preparation for the launch of the 10th government," said Moussavi, who was Iran's prime minister during the eight-year war against Iraq in 80s. Khatami, in a statement posted on his website khatami.ir earlier on Sunday, slammed the trial of detained activists as a "stage show" and said: "the confessions are not valid ... such a show would harm the establishment and the public trust." The June 12 presidential vote led to the re-election of hardline President Mahmoud Ahmadinejad. Moussavi and another defeated moderate candidate, Mehdi Karrubi, accused the authorities of rigging the election, prompting tens of thousands of their supporters to protest in Tehran and other major cities. Abtahi - a close aide of Khatami - was meanwhile quoted by the semi-official Fars news agency as expressing regret at having taken part in the protests. "I say to all of my friends who hear me that the issue of fraud in Iran was a lie, and was an excuse to create riots," the agency quoted Abtahi as having told the court. "Moussavi might not know the country well, but Khatami knew all the issues," it further quoted him as saying. "He was aware of the power of the country's leadership, but he joined Moussavi and that was a betrayal." "Our brothers, do not be sad. Be aware that the people can understand your situation and they are aware that protecting your lives is the most important thing for you," Mousaavi said. It was the first time since Iran's 1979 Islamic revolution that dozens of former officials and prominent activists have been put on trial together for acting against national security. Iran's state television reported this afternoon that the second session of trial will be held on Thursday. At least 20 people were killed during the protests, and over 1,000 political activists and journalists were arrested. Many were subsequently released, but about 250 reportedly remain in detention.