MOSCOW (AP) – Police moved to block thousands of ultranationalist demonstrators rallying in Russian streets on Saturday, arresting hundreds who gathered in defiance of a ban on far-right demonstrations.

A main organizer of the demonstrations, Alexander Belov, said rallies attracting thousands had taken place in more than 20 cities including Moscow, St. Petersburg, Krasnodar in southern Russia, Blagoveshchensk in the Russian Far East and the Siberian city of Novosibirsk.

He said police also detained activists in Novosibirsk and sought to block the marchers in a number of other cities.

The decision by authorities in the Russian capital and other cities to prevent the far-right supporters from marching, and the subsequent police response, appeared to mark an effort to dispel accusations that the government is doing little to combat rising xenophobia in Russia.

Russia has seen an increase in hate crimes against dark-skinned foreigners, Jews and immigrants from Central Asia and the Caucasus. This year, 39 people have been killed in apparent hate crimes and a further 308 attacked, according to the Sova rights center.

A year after security forces failed to intervene as marchers gave the Nazi salute and cried “Heil Hitler,” Moscow police enforced a ban on marches and carted away demonstrators. The demonstrations were timed to coincide with a Russian national holiday newly created last year.

Rights activists said Saturday that authorities still needed to do more.

“A systematic response is not just one event, but regularly prosecuting people for what they should be prosecuted,” said Alexander Verkhovsky of Sova.

Police in one Moscow street encircled groups of young men and hauled them off into buses, said Lidia Mikhailova, a spokeswoman for Dmitry Rogozin, a nationalist politician who had been involved in organizing the event.

Mikhailova told The Associated Press that she had seen dozens detained in this way and, citing other witnesses, estimated that several hundred people were taken into police custody.

Interfax news agency quoted a law enforcement source as saying that police detained more than 200 activists. A police desk officer in Moscow, who did not give his name, denied there were arrests.

Several hundred police, some wearing black helmets and carrying truncheons, surrounded a central square where up to 2,000 people rallied near a Russian Orthodox convent. Demonstrators waved flags from radical parties while some held religious icons.

Triumphant music played over loudspeakers. At one point, many in the crowd stretched out their hands in a Nazi-type salute.

Demonstrators complained of the presence in Russia of dark-skinned migrants from other former Soviet republics, whom they derisively refer to as “blacks.”

“I came here to remember that I am also a Russian man. I live well, I earn well, I have a family, but the blacks, they spoil my life,” said a 32-year-old man who identified himself only as Pavel.

Moscow Mayor Yuri Luzhkov forbade Saturday’s procession, saying that ultranationalists had used the Nov. 4 Day of People’s Unity last year to express extremist views.

“Don’t confuse German fascists with Russian patriots,” said a banner held up by a young man with close-cropped hair.

In Russia’s second largest city, St. Petersburg, police broke up a fist fight between several hundred far-right activists and antifascists. They detained dozens of ultranationalists for participating in a banned rally there, as well as a number of their leftist opponents, Interfax reported.

Meanwhile, liberal politicians and rights group held an authorized counter-rally in Moscow to protest the rise of xenophobia and to promote tolerance. About 500 people gathered holding flags with the words “Russian Anti-Fascist Front” and banners that read: “I am Russian and therefore not a fascist.”

The political and economic turmoil that followed the collapse of the Soviet Union generated hostility toward foreigners, especially millions of migrant workers. The trend has worsened in recent years despite a rise in incomes and political stability as authorities failed to crack down on extremist groups and hate crimes.