Riots broke out in the Belgian capital of Brussels after the national team lost 2-0 to Morocco in the second group match of the World Cup.
Around 100 police officers with water cannons had to take action against fans who destroyed street furniture and threw objects at the officers, the Belga news agency reported on Sunday afternoon.
There were also reports of riots in the Netherlands.
There was initially no information on the identity of the rioters.
In videos that are circulating on social networks and are supposed to show parts of the riots, several people can be seen with Morocco fan paraphernalia.
Brussels police urged people via Twitter to avoid Boulevard du Midi and adjacent streets in the city centre.
“The police have already intervened vigorously.
I therefore advise all fans not to come to the city center,” Brussels Mayor Philippe Close wrote on Twitter.
He had ordered the arrest of troublemakers.
At the request of the police, local transport in Brussels was partially stopped, as the local transport company also announced on Twitter.
According to a police spokeswoman, around 3:20 p.m., dozens of people had sought a confrontation with the law enforcement officers.
Among other things, pyrotechnics were used and fires were set on streets.
Belgium's Prime Minister Alexander De Croo criticized the violence and said according to Belga: "Football must be a celebration."
There was also unrest in the Netherlands - including in Rotterdam, Amsterdam and The Hague, as reported by the Dutch news agency ANP.
The police estimated the group of troublemakers in Rotterdam at 500 people.
Firecrackers and glass were thrown at the police.