BEIRUT AND TEHRAN — A sermon by powerful cleric and opposition supporter Ayatollah Ali Akbar Hashemi Rafsanjani reignited Iran's simmering protest movement Friday, heartening thousands of supporters who braved tear gas and club-wielding militiamen to march and chant slogans across Tehran.
In a 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 Ayatollah Ali Khamenei.
His speech, as well as the ensuing pitched clashes between security forces and supporters of opposition figure Mir-Hossein Mousavi, suggested that the political firestorm surrounding the marred vote would continue and that the movement it had inspired remained strong.
Reformist websites estimated that more than 1 million people participated. That number could not be confirmed, though even supporters of the hard-line camp who attended the prayer session to show support for Khamenei acknowledged that the crowds were huge.
Rafsanjani told worshipers gathered for Friday prayers in and around Tehran University: "We could have taken our best step in the history of the Islamic Revolution had the election not faced problems. Today, we are living in bitter conditions because of 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 claim that Ahmadinejad, backed by Khamenei, 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 Rafsanjani's speech 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 afterward, Tehran residents could be heard from rooftops and balconies 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 taking away young men in police vans. Helmeted Basiji militiamen aboard motorcycles began pushing toward crowds of young men and women brandishing eye-catching ribbons in green, the color of the opposition movement. Some women defiantly wore chadors in bright green instead of the traditional black.
After the sermon, downtown erupted in violence. Security forces attacked demonstrators, older and grayer than at recent gatherings, who were chanting "Death to the dictator!" and "God is great."
Tear gas filled streets as protesters sought to enter the gates of the university, which riot police had locked. The crowds swarmed through downtown, chanting slogans, lighting cigarettes and holding them in front of their faces to counter the effects of the tear gas.
Masked demonstrators also set fire to trash in the middle of roadways to burn off the tear gas, video posted on YouTube showed. One group shut down two highways, while a second handed flowers to smiling policemen and kissed them on the cheeks, witnesses said.
Another large group gathered in front of the Ministry of the 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.
A 50-year-old supporter of the hard-line camp, who identified himself only by his first name, Hossein, countered: "Mousavi caused all these problems. 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.