Red Star Belgrade and Partizan Belgrade fans clash in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. Serbian league leaders Partizan Belgrade held champions and bitter city foes Red Star to a 0-0 draw in a derby match marred by bad crowd trouble before kickoff on Saturday. The start was delayed for 45 minutes after home Red Star supporters pelted riot police with seats and flares, forcing officers to retreat from the north tier that houses the club's diehard fans. (Photo by Marko Djurica/Reuters)

Red Star soccer fans, left, clash with Partizan fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. Thousands of riot policemen have been deployed throughout Belgrade to prevent possible violence during a derby match between bitter rivals Red Star and Partizan. (Photo by Darko Vojinovic/AP Photo)

A Serbian riot police officer clashes with Red Star soccer fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Serbian riot police officers clash with Red Star soccer fan during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Serbian riot police officers clash with Red Star soccer fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

An injured Red Star Belgrade fan is helped by friends during clashes with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

An injured Red Star Belgrade fan is helped by a friend during clashes with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

An injured Red Star Belgrade fan sits during clashes with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

An injured fan is helped by a riot policeman during clashes between Red Star Belgrade and Partizan Belgrade fans in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade and Partizan Belgrade fans clash in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

An injured fan is helped by a riot policeman during clashes between Red Star Belgrade and Partizan Belgrade fans in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade and Partizan Belgrade fans clash in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade and Partizan Belgrade fans clash in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

An injured Red Star Belgrade fan is helped by friends during clashes with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

An injured Red Star Belgrade tries to jump over a fence during clashes with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Nebojsa Covic (C), vice President of Red Star Belgrade, tries to stop fans during clashes with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans clash with riot police in the stadium before their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans cheer amidst smoke during their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Partizan Belgrade fans cheer and light flares during their Serbian Superliga soccer match against Red Star Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans cheer amidst smoke during their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

Red Star Belgrade fans cheer and light flares during their Serbian Superliga soccer match against Partizan Belgrade in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)

A Serbian riot police officer clashes with Red Star fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Serbian riot police officers clash with Red Star soccer fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Serbian riot police officers clash with Red Star soccer fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Red Star soccer fans clash with police during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Serbian riot police officers clash with Red Star soccer fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Serbian riot police officers clash with Red Star soccer fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Serbian riot police officers clash with Red Star soccer fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Red Star soccer fans, left, clash with Partizan fans during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Partizan soccer fans light torches during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Red Star soccer fans clash with police during a Serbian National soccer league derby match between Red Star and Partizan, in Belgrade, Serbia, Saturday, April 25, 2015. (Photo by Darko Vojinovic/AP Photo)

Red Star Belgrade and Partizan Belgrade players stand on the pitch amidst smoke during their Serbian Superliga soccer match in Belgrade, April 25, 2015. (Photo by Marko Djurica/Reuters)