BELGRADE, Serbia — Authorities say at least 50 people have been injured and 40 arrested after fierce clashes between Red Star and Partizan fans.

The riots erupted before the match between the two biggest Belgrade rival clubs at the Red Star stadium in the capital on Saturday.

The start of the match had to be postponed for 40 minutes when hooligans hurled stones at each other and battled with sticks. The play was also stopped for seven minutes because of flares hurled on to the pitch.

Several fans were seen bloodied. Police say 20 officers were injured when they tried to separate the fighting groups.

The match ended in a goalless draw, giving Partizan a five-point lead over Red Star in the standings.