Gay rights protesters are taken away by riot police in Moscow on Saturday. About 40 people were arrested. (Alexander Zemlianichenko/Associated Press)

As performers from across Europe prepared to compete in Moscow on Saturday night in the Eurovision song contest, one of the most watched annual TV events in the world, riot police broke up gay pride rallies.

Gay rights activists sought to use the international competition to draw attention to what they call widespread discrimination against homosexuals in Russia.

Several hours before the show began, riot police broke up gay pride rallies in the Russian capital, setting back Moscow's efforts to use the event to showcase the country's hospitality and prestige. No injuries were reported.

Police hauled away around 40 demonstrators, including Britain-based activist Peter Tatchell and Andy Thayer of Chicago, co-founder of the Gay Liberation Network.

"Today's arrests go against the principles of Eurovision, which are about peace, harmony, co-operation and unity between all the peoples in Europe," Tatchell told The Associated Press after being released by police.

The winner of the song contest is picked by a combination of telephone voting and official juries from national broadcasters in the 42 competing countries.

Twenty-four artists and bands were competing as finalists.

Norway's entry, an upbeat emotional ditty penned and performed by Belarus-born Alexander Rybak, was strongly tipped to snatch the Eurovision crown from Russia, which won the competition last year.

Russia was pinning its hopes on Mamo, an overwrought ballad composed by a Georgian songwriter and partly performed in Ukrainian by a Ukrainian-born artist Anastasia Prikhodko.

Moscow authorities have worked hard to turn the Eurovision contest to display Russia's hospitality and prestige, splashing out 24 million euros ($38.2 million Cdn) on the show and a week-long series of decadent parties.