Racism and right-wing violence are threatening Russia's reputation in international sports as the country prepares to host the Winter Olympics in February and the World Cup soccer finals in 2018.
The latest incident was a riot at a soccer match last week in Yaroslavl, between the local Shinnik (Tiremakers) team and Spartak, a squad from Moscow.
Fights broke out along the barrier between the opposing fans, then Spartak fans ripped up stadium seats and threw them at riot police who tried to drive the fans back with blasts from a water cannon.
The Spartak fans launched fireworks at the police and brandished a Nazi flag with a swastika.
The week before in the Russian capital, fans of CSKA Moscow threw bananas and yelled racist monkey chants at black players from the British team Manchester City.
The incident prompted Manchester City star Yaya Toure, who comes from the Ivory Coast, to call on all black players to boycott the 2018 World Cup if Russian attitudes don't change. Yaroslavl, CSKA Moscow and Spartak Moscow are all teams whose home grounds will be among the 14 venues of the Russia 2018 World Cup.
The fans of FC Zenit, based in St. Petersburg, may be the most notorious for racist and homophobic attitudes. Last year, the biggest Zenit fan club, Landscrona, issued a manifesto demanding that the club field an all-white, heterosexual team.
It claimed "dark-skinned players are all but forced down Zenit's throat now, which only brings out a negative reaction," and said gay players were "unworthy of our great city."
The club quickly distanced itself from that manifesto.
Racism isn't the only problem that worries international sports fans about Russia.
A new national law that limits the rights of lesbian, gay, bisexual and transgender people has raised questions about how LGBT athletes and spectators will be treated at the 2014 Winter Olympics in Sochi.
Russian President Vladimir Putin says that people of different sexual orientations will be welcome at the games, and that they will be protected.
A Larger Russian Issue
Not all sports in Russia have had problems with racism. Black players are among the most celebrated in Russia's basketball leagues, and they have played on the Russian national team.
The world track and field championship was held this past summer in Moscow without any incidents.
However, racism in Russian sports may reflect a growing climate of xenophobia in the country, and it is most often directed at immigrants from Central Asia and the Muslim population from Russia's Caucasus region.
Over the summer, there were a string of confrontations in Moscow at vegetable markets that employ migrant workers.
Last month, the murder of a young Slavic man by an immigrant from Azerbaijan triggered a riot by Slavs who attacked a market and beat up workers who were non-Slavic.
Police responded by rounding up migrant workers and detaining many of them.
Several thousand Russian nationalists rallied Monday in Moscow, using the national holiday of Unity Day to vent their anger against migrants, whom they accuse of boosting crime and taking jobs from Slavic Russians.
The United Nations reported in September that Russia has about 11 million migrants, yet Russian authorities say only about 700,000 are legally registered.