TEHRAN, Dec. 20 As protests broke out last week at a prestigious university here, cutting short a speech by President Mahmoud Ahmadinejad, Babak Zamanian could only watch from afar. He was on crutches, having been clubbed by supporters of the president and had his foot run over by a motorcycle during a less publicized student demonstration a few days earlier.
But the significance of the confrontation was easy to grasp, even from a distance, said Mr. Zamanian, a leader of a student political group.
The student movement, which planned the 1979 seizure of the American Embassy from the same university, Amir Kabir, is reawakening from its recent slumber and may even be spearheading a widespread resistance against Mr. Ahmadinejad. This time the catalysts were academic and personal freedom.
"It is not that simple to break up a president's speech," said Alireza Siassirad, a former student political organizer, explaining that an event of that magnitude takes meticulous planning. "I think what happened at Amir Kabir is a very important and a dangerous sign. Students are definitely becoming active again."
The protest, punctuated by shouts of "Death to the dictator," was the first widely publicized outcry against Mr. Ahmadinejad, one that was reflected Friday in local elections, where voters turned out in droves to vote for his opponents.
The students' complaints largely mirrored public frustrations over the president's crackdown on civil liberties, his blundering economic policies and his harsh oratory against the West, which they fear will isolate the country.
But the students had an additional and potent source of outrage: the president's campaign to purge the universities of all vestiges of the reform movement of his predecessor, Mohammad Khatami.
Last summer the newly installed head of the university, Alireza Rahai, ordered the demolition of the office of the Islamic Association, which had been the core of student political activities on campus since 1963 and had matured into a moderate, pro-reform group.
Since then, students say, more than 100 liberal professors have been forced into retirement and many popular figures have been demoted. At least 70 students were suspended for political activities, and two were jailed. Some 30 students were given warnings, and a prominent Ph.D. candidate, Matin Meshkin, was barred from finishing his studies.
The students also complain about overcrowded and crumbling dormitories and proscriptions against women wearing makeup or bright colors, rules that were relaxed when Mr. Khatami came to power in 1997.
Amir Kabir University of Technology, a major polytechnic institute, has been a hotbed of student activism since before Ayatollah Ruhollah Khomeini's Islamic Revolution of 1979. Drawing on networks at universities around the country through an office that links their Islamic associations, students can organize large protests on a moment's notice. There are also student guilds, which are independent, and more than 2,000 student publications.
Mr. Zamanian, the head of public relations of the Islamic Association at Amir Kabir, said that while the situation had not been ideal in the Khatami years, Mr. Ahmadinejad's antireformist campaign had led students to value their previous freedoms.
They were permitted to hold meetings and invite opposition figures to speak, he said, and could freely publish their journals. Now, he said, their papers are forbidden to print anything but reports from official news agencies.
The students also complain about the president's failure to deliver economic growth and jobs. At last week's protest, which coincided with a now infamous Holocaust conference held by the Foreign Ministry, students chanted, "Forget the Holocaust do something for us."
A student who identified himself only as Ahmad, for fear of retribution, said: "A nuclear program is our right, but we fear that it will bring more damage than good."
Another student said: "It is so hard and costly to come to this university, but I don't see a bright future. Even if you are lucky enough to get a job, the pay would not be enough for you to pay your rent."
Mr. Zamanian said that the protest had not been planned ahead of Mr. Ahmadinejad's visit, but that students were further enraged when they saw supporters of the president being bused in.
Although the auditorium was almost filled with the president's supporters by the time any students were let in, the protesters forced their way inside, chanted, "Death to the dictator," and held banners calling him a "fascist president." They also held up posters of the president with his picture upside down and set fire to three of them. Many of the students are now in hiding.
At one point, the head of a moderate student guild complained to Mr. Ahmadinejad that students were being expelled for political activities and given three stars next to their names in university records, barring them from re-entering. The president responded by ridiculing him, joking that the three stars made them sergeants in the army.
The president was eventually forced to cut his speech short and leave. But angry students stormed his car, kicking it and chanting slogans. His convoy of four cars collided several times as they tried to leave in a rush. Eventually the students were dispersed.
An entry on Mr. Ahmadinejad's Web log, posted Wednesday, played down the scale and significance of the protest, writing that the president had a "good feeling when he saw a small group amid the dominant majority insulting him without any fear."
A few days after the protest, former Amir Kabir students affiliated with the Islamic associations' coordinating office wrote a letter to Mr. Ahmadinejad. In it, they turned down what they said was his invitation to share their problems with him, because they believed that he wanted to use the occasion to bolster his candidates in the local elections.
The students also wrote that the president had insulted their intelligence by talking to them in the same language he uses in remote villages on his provincial trips.
"You should know that what happened at Polytechnic University was the voice of universities and the real voice of the people," they wrote. Tehran Polytechnic was the university's name before the revolution.