Two incidents occurred last night, the first at Zagreb's central square about 40 minutes after midnight, when a 54-year-old Zagreb resident wearing a Zvezda outfit was provoking passers-by.
A group of 12 young men tried to assault him, but the police intervened and several youths assaulted the police, one of them hitting an officer with a wooden stick.
All 12 youths were taken into custody and will not be released today. The 54-year-old was also taken into custody because he continued to hurl insults and provoke.
The second incident occurred shortly before midnight, when the police saw about 10 youths collecting stones around Maksimir stadium. When they saw the police, the youths started running, but three were caught and brought into custody.
About 1,000 police will guard today's match.