More than 50 people were injured, including three policemen, and a hundred arrests were made in clashes this Thursday in a suburb of Stockholm between supporters of the Eritrean government, who had organized a festival, and an opposition group.

The incidents turned into a pitched battle, with several vehicles set on fire, while the opposing groups attacked each other with sticks and stones and a strong police force tried to separate them, reports the Aftonbladet newspaper. The riots began when a group of protesters broke through the police cordon and attacked the party participants, according to that outlet.

The police later reported that they have detained a hundred people, while at least seven of the injured were admitted with serious injuries. Traffic on a nearby highway was cut off by law enforcement when several people invaded the road.

“It is a complicated and extensive operation. There are many people on the move and the total damage is not yet clear,” Stockholm region chief physician Patrik Söderberg said in a statement.

The Eritrea Scandinavia festival has been organized for three decades in the Swedish capital and has previously been criticized for supporting the Eritrean regime. Similar incidents recently took place in Germany at a party also organized by the pro-regime group, sparking protests from opposition protesters.