Serbian police have fired tear gas at anti-government protesters in downtown Belgrade as they clashed for the third day on the streets of the country's capital and other cities amid reports of police brutality and excessive use of force during the unrest.

Serbian President Aleksandar Vucic has announced tough measures against antigovernment protesters following days of riots challenging his rule.

Protests against the government of President Aleksandar Vučić in Serbia saw a fourth consecutive day of violence on Saturday night. The most severe riots occurred in the central town of Valjevo, where opponents of the government set fire to the office of Vučić's Serbian Progressive Party (SNS) and damaged buildings of the city administration and the local public prosecutor's office.

Anti-government protesters demolished the offices of the ruling Serbian Progressive Party (SNS) in the northern city of Novi Sad and clashed with police and SNS supporters in the capital Belgrade on Thursday,

Serbia's police say they have detained scores of demonstrators who took part in anti-government protests throughout the country this week.

Angry protesters clashed with police in a town in western Serbia and in the capital Belgrade on Saturday as tensions soared further in the Balkan nation following days of violent demonstrations. Wearing scarves over their faces and chanting slogans against President Aleksandar Vucic,

The sometime actor and former Yugoslavian soccer player sold the eatery, which last year celebrated its 60th anniversary, to current owner Sonja Perencevic in 2009 before moving to Belgrade, Serbia.