Police have reported violence between fans of football clubs FC Basel and AS Roma before and after their Europa League match in the northern Swiss city.
Local authorities said 11 people were arrested on Thursday and three police officers were slightly injured. Nine were apprehended before the game.
Police had prepared for violence outside the St Jakob stadium with a "massive" presence, they said. Officers from cantons Basel City, Basel Country, Aargau and Bern had been brought in, according to the Swiss News Agency.
Hoodlums attacked each other "suddenly", police said. Supporters of the Swiss and Italian sides also vandalised cars, threw bottles and the Italian flag was desecrated.
The amount of damage was not released. The violence calmed down 30 minutes after the game, police said.
FC Basel inflicted a surprise defeat on Roma, winning the game 2-0.
swissinfo.ch and agencies
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