MOSCOW -- Thousands of people turned out Monday for a protest here that was intended to draw attention to what organizers said was the return of political prosecutions in the Russian courts.
The rally, one of the largest protests in recent months, was timed to coincide with the anniversary of a riot in Bolotnaya Square last year that was followed by mass arrests and prosecutions under contentious circumstances. The prosecutions are known collectively as the Bolotnaya Case.
That demonstration signaled the end of the winter's large, peaceful protests. It also precipitated a series of laws enacted under President Vladimir V. Putin that constricted the rights to assemble and increased fines for unsanctioned gatherings.
Organizers said nearly 30,000 people attended the rally on Monday, close to their expectations and the limit allowed under the permit for the gathering. Interfax, a Russian news agency, said turnout was closer to 8,000.
Regardless, the rally showed that organizers could still draw thousands to a park in the center of Moscow to protest politically oriented arrests and prosecutions.
Police arrested five people for wearing masks, which is illegal, and one person for lighting a flare. But over all, the event was peaceful.
"It's understood that something powerful and something frightening to some has come out on the street," Aleksei A. Navalny, a prominent opposition leader who is on trail on an old -- and some say questionable -- embezzlement charge, told the crowd. "I am part of that frightening thing. It is enormous. It is the people."
Mr. Navalny, who faces a maximum sentence of 10 years in prison, said he would not be intimidated. "I will go on speaking the truth" to create a better Russia, he told the crowd. "I don't have another country or another family or another people except you."
Before the protest got under way on Monday, a volunteer was killed in an accident while helping erect the stage, forcing the organizers to improvise by shifting the podium to a flatbed truck.
Gennady Gudkov, an opposition leader and former member of Parliament, said at the rally that the turnout showed that Russians will not succumb to fear. "Arrests and prosecutions are their means of scaring people," he said. "This is their way of saying, 'If you come out, the same will happen to you, too.' "
Some demonstrators on Monday wore buttons that read "The Case Against Navalny Is the Case Against Me!"
Maria Kedrina, a hotel employee, said she came because "any one of us could be a political prisoner."
Igor M. Bunin, the director of the Center for Political Technologies in Moscow, said protest organizers were hoping to send a message that would give the Kremlin pause before sentencing Mr. Navalny to prison.
The Bolotnaya case has galvanized the Russian opposition. It began with the protest a year ago as the police herded tens of thousands of people from Bolshaya Yakimanka, a broad street, into a rows of riot police officers who formed a human funnel toward an entrance to Bolotnaya Square where there were not enough metal detectors.
Fights broke out, and people tore the helmets off some police officers and threw them into a canal. Several officers were hospitalized. When the police began striking protesters with batons and making arrests, marchers caught in the crush of people were pushed toward a narrow bridge, and it seemed that some might be pushed into the water.
The violence became politically advantageous President Putin by justifying the subsequent arrests and prosecution, political analysts say.
The police detained about 400 people that day, and arrests followed in three waves over the next year. The Bolotnaya case is continuing, and the authorities have prosecuted 28 people for assaulting policemen and taking part in and organizing a mass disturbance.
In a more ominous development for the protest movement, the Russian television channel NTV broadcast a documentary not long after the protest asserting that more than an unruly crowd was to blame for the violence. Members of the opposition had organized the violence, the documentary asserted, and the police soon took up the same theme.
The authorities say three protest leaders -- Sergei Udaltsov, Konstantin Lebedev and Leonid Razvozzhayev -- took money from a Georgian politician to provoke the street fight. The trio became the best known of the Bolotnaya case prisoners who were the inspiration of the rally on Monday.
Mr. Udaltsov denied the charges and is under house arrest in Moscow. Mr. Razvozzhayev, who had fled to Ukraine, said he was kidnapped on a street in Kiev and then held captive by unknown men in conditions tantamount to torture until he signed a confession, which he recanted. He faces 10 years in prison. Mr. Lebedev confessed and was sentenced to two years and six months in jail.
This article originally appeared in The New York Times.