MOSCOW, May 1 (RIA Novosti) - About 400,000 Russians on Friday celebrated Spring and Labor Day, with trade unions and political parties holding rallies across the country.

"As of 15:00 Moscow time [11:00 GMT], 491 demonstrations, rallies and assemblies took place in Russia, with about 400,000 people participating," police said, adding that 32,000 police and Interior Ministry troops worked to ensure public order during the events across Russia.

May 1 is Spring and Labor Day across Russia, a national holiday. In Soviet times May 1 saw massive Communist Party rallies.

Moscow police reported earlier in the day that as around 25,000 people were taking part in events in downtown Moscow to mark the day, including demonstrations by the ruling United Russia party, the Communists and trade unions, the ultranationalist LDPR Party and the liberal Yabloko party.

No public order problems were reported in Moscow, but police have detained 120 nationalists, anti-fascists and anarchists following demonstrations in St. Petersburg. Police seized a number of knives and rubber-bullets pistols.