Authorities in North Macedonia have arrested 21 people following clashes between visiting Levski Sofia soccer fans and Shkupi supporters ahead of a Europa Conference League qualifying match.

Police said Friday that 19 Bulgarians and two people from North Macedonia were detained because of Thursday's violence, which came amid uneasy relations between the two Balkan neighbors.

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The clashes started after local Shkupi fans attacked traveling Bulgarians in Skopje, stabbing one man in the stomach. No arrests have been made over that incident, and police said the injured Levski supporter was in stable condition after undergoing surgery.

Levski fans later clashed with police. Levski won the game in Skopje 2-0.

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North Macedonia’s government condemned the violence, which Prime Minister Dimitar Kovachevski blamed on "hooligans and people who have nothing to do with sports."

Relations between North Macedonia and Bulgaria have been poor amid disputes over history, identity and cultural heritage that led to Sofia blocking its neighbor’s European Union accession bid in 2020.