Video clips show how the government supporters are throwing distress rockets, stones and bottles at the demonstrators, who in turn throw back various objects.
Among the dozens injured are 16 police officers, according to the police. Similar unrest is reported to have occurred during demonstrations in other parts of the country.
The protests, mainly against Serbia's president Aleksandar Vucic, have been organized for more than nine months. The starting point was an accident at the train station in the city of Novi Sad, when the station's roof collapsed, resulting in 16 people being killed. The demonstrators see the accident as a consequence of corruption in the government and have since then demanded Vucic's resignation.
