Dinamo Zagreb-Red Star Belgrade riot

The Dinamo Zagreb–Red Star Belgrade riot was a football riot which took place on 13 May 1990 at Maksimir Stadium in Zagreb, Croatia between the Bad Blue Boys (fans of Dinamo Zagreb) and the Delije (fans of Red Star Belgrade). The incident took place just weeks after Croatia's first multi-party elections in almost 50 years in which the parties favouring Croatian independence had won the majority of votes. The riot resulted in over 60 people wounded, including some stabbed, shot or poisoned by tear gas.

Tension between the two teams was always high as they consistently placed at the top of the Yugoslav football league and often won the national championships. In 1990, this took an even worse character due to rising ethnic tensions in Yugoslavia. The first multi-party elections were held in most of Yugoslavia and communism was ousted in favour of more national-oriented parties. The second round of voting in Croatia was held on 6 May when the Croatian Democratic Union (HDZ) won under Franjo Tuđman. Slovenia and Croatia, under new leadership, were the leading forces behind a drive to reorganize Yugoslavia into a confederation, but were opposed by Serbia under Slobodan Milošević and the still powerful Communist system at state-level. Approximately 3,000 Delije made the trip to Zagreb. They were led by Željko Ražnatović (also known as "Arkan"), a Serbian nationalist who led the Serb Volunteer Guard. Between 15,000 and 20,000 spectators were estimated to have attended the game.

...
Wikipedia