Six fans were injured, two of them seriously, when rival fans clashed shortly before a ULEB Cup basketball match between Serbia's Red Star Belgrade and Greek side PAOK Salonika on Tuesday.

"Two of the six injured fans have sustained serious injuries but none of them are in critical condition," said Slobodan Ivanovic, a spokesman for Belgrade's Anlave clinic.

Supporters of Red Star and their city rivals Partizan, who had joined a handful of visiting PAOK fans, invaded the court and pelted each other with flares as well as seats they ripped from the tiers before riot police moved in to quell the violence.

Encounters between Red Star and Partizan in both soccer and basketball have a history of crowd trouble and more than 100 fans were injured when an entire tier collapsed amid clashes during their basketball derby in June.