Russian hooligan groups are planning to cause "significant fear" at the 2018 World Cup following violent attacks and racist behavior at the European Championship, anti-discrimination organization the Fare Network has warned.

In a report analyzing cases of racism and discrimination at Euro 2016, the UEFA-affiliated Fare Network says fans of eight of the 24 teams at the tournament, including England, were involved in discriminatory incidents in and around stadiums.

The incidents range from racist and homophobic slogans to the mass street violence involving English and Russian fans in Marseille ahead of a group stage game between the two countries last month.

Fare, which posted observers at Euro 2016 games, says well-organized Russian hooligan groups with racist links "may be tempted by the prospect of causing isolated harm and creating significant fear during the Confederations Cup 2017 or World Cup in 2018" and calls on the Russian government to do more to stop them.

"We remain concerned about the prospect of ongoing far-right involvement in Russian football," the report says. "This and the organized nature of their hooligan groups — as seen through the levels of violence they used in Marseille in particular — need addressing urgently by Russian authorities."

Fare says it has "significant concerns" that fans "of a visible African or Asian heritage or those from the LGBT community" could be attacked if they visit some World Cup host cities.

After the violence in Marseille, three Russian fans were sentenced to prison terms of between one and two years, while 20 more were deported from France, including a fan leader with a role in organizing World Cup preparations on a Moscow city government commission.

Besides street violence, Fare says some Russia fans wore clothes with racist symbols, displayed far-right banners at a game and "were reportedly performing monkey chants toward stewards."

Some England fans were also seen chanting sexist and "xenophobic anti-migrant chants," and filmed "mocking" children from the Roma minority, also known as Gypsies, by throwing coins for them to chase.

Croatia also comes in for heavy criticism by Fare, which highlights cases at three separate games in which fans chanted or displayed flags in support of the World War Two-era Ustase fascist movement. Meanwhile, a group of German fans performed Nazi salutes and attacked Ukrainian supporters ahead of a group stage game, according to the report.

Fans from Spain, Poland, Ukraine and Hungary were also censured for racism-related conduct.

Despite highlighting discriminatory conduct by eight teams' fans, Fare says that UEFA punishments for teams had prevented more incidents.

"The overall levels of major discriminatory incidents recorded inside stadiums were not as high as they could be and have been at other tournaments," the report says. "Fan conversations that we monitor on social media and message boards often follow a line that certain banners and chants should be kept to matches at national level to avoid risk of severe collective sanction from UEFA."