Police detained hundreds of people in Moscow on Saturday, including young nationalists who rallied in the northern part of the city, as part of a clampdown to prevent new outbreaks of ethnic violence.
The arrests came a week after roughly 7,000 soccer fans and nationalists chanting racist slogans demonstrated near Red Square and attacked passersby who appeared to be ethnic minorities, injuring more than 30 people.
Those attacks, which highlighted simmering ethnic tensions in the country, have been condemned by President Dmitry Medvedev as "pogroms."
In a sanctioned demonstration on Saturday under the Ostankino television tower in the north of Moscow, hundreds of young Russian nationalists gathered and shouted slogans such as "Patriotism is not Fascism."
"The rally was sanctioned, but soon the young people got bored, split into groups and started marching with flaming torches toward the metro. This was illegal, of course, and the police made arrests," said Moscow police spokesman Viktor Biryukov.
He said there had been no violence and that most of the demonstrators were in their early teens. Arrests also were made at unsanctioned protests in other parts of the city.
Moscow police said about 500 arrests had been made and that weapons, including knives and stun guns, had been confiscated.
News agencies reported that some people of migrant origin had also been detained.
Authorities had launched a similar crackdown Wednesday, detaining about 800 Russian youths and migrants from the Caucasus and Central Asia who had been gathering for a rumored confrontation near the Kievsky railway station.
Prime Minister Vladimir Putin said Thursday during a televised question-and-answer session with Russian Federation viewers that all forms of extremism must be prevented.