Serbia's Football Association president Slavisa Kokeza was questioned by police on Sunday in connection with arrests of members of a fan group.
Serbian police raided the stadiums of the country's two biggest football clubs on Thursday after arresting 17 people linked to organized crime.
Manchester United cruised to a 3-0 win over FK Partizan in Europe League group stage action.
Manchester United climbed atop Group L with a 1-0 victory at Partizan Belgrade in the Europa League on Thursday.
Paul Pogba and David De Gea were among the notable absentees in training for Manchester United ahead the Europa League clash with Partizan Belgrade.
Liverpool will undergo a light training session at the Partizan-Teleoptik complex, also known as Zemunelo, on the morning of Nov. 6.
Five Croats who were arrested in Serbia after a massive fan brawl at a Belgrade derby last month will serve four to six months in prison.
Partizan Belgrade and Red Star's derby match was marred with violence between fans in which 20 people were injured, one with severe head injuries.
Russian club Zenit St. Petersburg are facing a UEFA racism charge after their fans displayed a large banner with convicted war criminal Ratko Mladic.
UEFA president Aleksander Ceferin has warned the Serbian clubs that they could be kicked out of European competitions because of riots and racism.
CAS has overturned Partizan Belgrade's three-year ban from European club football after the Serbian side presented new evidence.
Partizan Belgrade defender Nikola Milenkovic is set to join Fiorentina in a €5.1 million deal this summer, the Serbian Super Liga club have announced.
The Brazilian, who joined Partizan last year, played through monkey chants
UEFA has banned Partizan Belgrade from the Champions League and Europa League for the next three seasons because of unpaid debts.
Zivkovic, 19, is out of contract in June and earlier this month Le Parisien reported that both PSG and Manchester City were considering making a bid.
Manchester United have been drawn against Club Brugge in the Champions League playoffs.
Chelsea signed teenage midfielder Danilo Pantic from Partizan Belgrade on Thursday and loaned him to Dutch side Vitesse Arnhem.
Ludogorets Razgrad's Champions League dreams came to an early end on Tuesday as they bounced out of the competition in the second qualifying round.
Two of last season's Champions League group-stage underdogs got off to a rough start in the first leg of the second qualifying round on Tuesday.
Red Star and Partizan's most recent derby was notable not for what happened in the game, but rather for events in the stands, writes Andy Mitten.
Authorities say at least 50 people have been injured and 40 arrested after fierce clashes between Red Star and Partizan fans.
Tottenham face UEFA sanctions after their Europa League tie with Partizan Belgrade was suspended, overshadowing their progress to the knockout stages.