In his highly anticipated speech, Rafsanjani slammed the hard-line camp supporting President Mahmoud Ahmadinejad, criticized the June 12 election results and promoted several key opposition demands. Analysts said his description of the unrest as an ongoing 'crisis' was a signal to keep the pressure on Ahmadinejad and Supreme Leader Ali Khamenei. His speech, as well as the pitched clashes between security forces and supporters of opposition figure Mir-Hossein Mousavi that followed, suggested the political firestorm unleashed by the marred vote would continue and that the movement it had inspired remained strong. 'We could have taken our best step in the history of the Islamic revolution had the election not faced problems,' he told worshippers in and around Tehran University. 'Today, we are living in bitter conditions due to what happened after the announcement of the election result. All of us have suffered. We need unity more than any time else.' Mousavi and his supporters say Ahmadinejad, backed by the supreme leader, falsified results and stole the election. Khamenei, who is supposed to be above partisan politics, infuriated them by coming down squarely on the side of the incumbent. Mousavi's backers widely interpreted the speech by Rafsanjani as anything but a call for unity. They chanted boisterous anti-government slogans for hours in defiance of menacing security forces and plainclothes Basiji militiamen. Immediately after the speech, Tehran residents could be heard from rooftops and balconies in various districts shouting support for Rafsanjani. 'The main goal of Rafsanjani's sermon today was to improve his own position so that he can pressure Khamenei,' said Meir Javedanfar, an Iran analyst. 'He got large numbers to come to the streets and to listen to him. He showed that he is not a spent force.' Even before the speech, security forces were stuffing young men into police vans. Helmeted Basiji militiamen aboard motorcycles began pushing toward crowds filled with young men and women brandishing eye-catching ribbons in green, the color of the opposition movement. Some women defiantly wore all-covering chadors in bright green. After the speech, downtown Tehran erupted in violence. Security forces attacked crowds of demonstrators, older and grayer than recent gatherings, who were chanting 'Death to the dictator!' and 'God is great.' Tear gas filled streets as demonstrators sought to enter the gates of Tehran University, which riot police had locked. The crowds swarmed through downtown, chanting slogans, lighting cigarettes and putting them in front of one another's faces to ward off the effects of tear gas. (Begin optional trim) Masked demonstrators also set trash fires in the middle of roadways to burn off the tear gas, videos posted on YouTube showed. One group shut down two highways, while a second handed flowers to smiling policemen and kissed them on the cheeks, according to witnesses. Another large group gathered in front of the Ministry of Interior, which is under the control of Sadegh Mahsouli, a wealthy ally of Ahmadinejad. 'Mahsouli! Mahsouli! Give my vote back,' they chanted, according to a video posted to YouTube. Demonstrators also began to head north to approach the headquarters of state broadcasting, which has barely reported on the unrest and aired a cooking show on television during Rafsanjani's speech. 'Last Thursday five of my friends were arrested, and they are in ... Evin Prison, and it's my duty to come and participate,' said Nahid, a 22-year-old law student who asked that her last name not be published. (End optional trim) Reformist Web sites estimated that more than 1 million people participated. That could not be confirmed, but even supporters of the hard-line camp who attended the prayer session to show support for Khamenei acknowledged that the crowds were huge. 'Mousavi caused all these problems,' said a 50-year-old man who identified himself only by his first name, Hossein. 'This is his fault.' As night fell, the boisterous roar of 'God is great' could be heard from rooftops across the capital in what has become a daily gesture of protest against Ahmadinejad, who is to be sworn in for a second term early next month. Mousavi and fellow reformist presidential candidate Mehdi Karroubi attended the sermon, according to photographs published by the semi-official Iranian Students News Agency. Plainclothes security officers roughed up Karroubi after the speech, knocking his turban to the ground, according to witnesses and photographs posted online. (Begin optional trim) At times during the prayer service, the two camps appeared to be shouting directly at each other. As Mousavi supporters chanted 'Death to the dictator' against Ahmadinejad, his supporters chanted 'Death to opponents' of Khamenei. And as hard-liners repeated their signature cries of 'Death to America' and 'Death to Israel,' Mousavi supporters overwhelmed them with chants of 'Death to Russia' and 'Death to China,' referring to the two U.N. Security Council members that have shielded Iran from much tougher sanctions over its nuclear program. (End optional trim) Asked about the day's developments, U.S. State Department spokesman Robert Wood told reporters that Iran's government needed to address a crisis of confidence. 'And until it does, it's going to be very hard for that government to gain legitimacy in the eyes of its people,' he said. Rafsanjani's sermon did not appear to alter for now the dynamics within the ruling establishment and Iranian society. But it gave explicit clerical backing for some of the key demands of the movement built on Mousavi's presidential campaign. By calling for the rule of law, he positioned himself as a statesman and took a swipe at Khamenei. Although diplomatic, he placed himself squarely within the opposition camp. His speech appeared to strike a chord with ordinary Iranians, bolstering Rafsanjani's status among Iran's middle class, who had long derided him as corrupt. 'Most of people are so glad that Rafsanjani made such a speech,' said Ali, a 34-year-old computer programmer who previously described himself as a supporter of the deposed family of Shah Mohammad Reza Pahlavi. 'We think that he is a hero and this action will cause him to remain a hero all his life.' Rafsanjani urged tolerance and dialogue but criticized the election results and the treatment of dissidents. 'All of us -- the establishment, the security forces, police, Parliament and even protesters -- should move within the framework of law,' Rafsanjani said. 'We should open the doors to debate. We should not keep so many people in prison. We should free them to take care of their families.' He criticized the powerful Guardian Council for its review of the election results and said all Iranians needed to 'restore public confidence because it was badly damaged.' He said healing will take time and that utilizing the blunt instruments of state to quiet dissent would only make matters worse. He demanded freedom of the press. Media-monitoring groups say dozens of Iranian journalists have been jailed. 'We should let our media even criticize us,' he said. 'Our security forces, our police and other organs have to guarantee such a climate for criticism.' He also called for justice for the families of those killed in post-election violence. 'We should try to console them,' he said. Special correspondent Mostaghim reported from Tehran, and Times staff writer Daragahi from Beirut, Lebanon. 