Riots broke out in several Belgian and Dutch cities after Morocco’s 2-0 upset win over Belgium at the World Cup Sunday.

Police detained about a dozen people after they deployed water cannons and fire tear gas to disperse crowds in Brussels and eight more in the Northern city of Antwerp. Two police officials were injured in the Dutch port city of Rotterdam. By late evening Sunday, an uneasy calm had returned to most of the cities involved.

Dozens of rioters overturned and torched cars, set electric scooters on fire and pelted cars with bricks. Police moved in after one person suffered facial injuries, said Brussels police spokeswoman Ilse Van de Keere.

Read more: What happened to Morocco's first-choice GK before kickoff v Belgium?

Brussels mayor Philippe Close urged people to stay away from the city center and said authorities were doing their utmost to keep order in the streets. Even subway and tram traffic had to be interrupted on police orders.

“Those are not fans, they are rioters. Moroccan fans are there to celebrate,” Close said. There were also disturbances in the city of Antwerp and Liege.

“Sad to see how a few individuals abuse a situation to run amok,” said Interior Minister Annelies Verlinden.

Police in the neighboring Netherlands said violence erupted in the port city of Rotterdam, with riot officers attempting to break up a group of 500 soccer supporters who pelted police with fireworks and glass. Media reported unrest in the capital Amsterdam and The Hague.

Read more: Morocco beat Belgium 2-0 pulling off another shock at World Cup

Morocco’s victory was a major upset at the World Cup and was enthusiastically celebrated by fans with Moroccan immigrant roots in many Belgian and Dutch cities.