MOSCOW -- Several thousand Russian nationalists rallied Monday in Moscow, venting against the migrants they accuse of pushing up the crime rate and taking their jobs.

The protest took place on the national holiday of Unity Day, established in 2005 to replace commemorations of the Bolshevik Revolution.

Many demonstrators carried Russian imperial flags. One group displayed a banner reading "Young People Against Tolerance." The protesters in a southern neighbourhood of the Russian capital ranged from tough-looking youths to older people.

Animosity is strong among nationalists against migrants both from the former Soviet Central Asian republics and non-Slavs from the largely Muslim Russian Caucasus region.

Monday's rally came three weeks after rioters targeted a vegetable warehouse where they believed the killer of an ethnic Russian man was working. Police later rounded up more than 1,000 migrants working at the warehouse.

Some demonstrators praised the riot and suggested it was backed by the state.

"People received a signal that if they engage in such pogroms, there will be progress," said Yevgeny Morgunov, a 36-year-old researcher at the Russian National Academy of Sciences.

He said he didn't support the radical exclusionary sentiment reflected in the nationalist slogan "Russia for Russians," but said "if Russians feel good, the other people of Russia will feel it too."

There were no immediate reports of trouble at the Moscow rally, but the Interfax news agency said police detained 12 participants in a similar rally in the Siberian city of Krasnoyarsk. Nationalist demonstrations were also reported in the cities of Irkutsk and Kazan.

A UN report in September said Russia has about 11 million migrants. The state news agency RIA-Novosti, however, cited the Federal Migration Service as saying only about 718,000 of them have residency permits.