Angry protesters have set fire to the offices of Serbia's governing populist party in a western town and clashed with police in the capital Belgrade in another evening of violent protests shaking the Balkan country.

Serbia's police used teargas and crowd control vehicles on Friday evening in Belgrade to disperse anti-government protesters who threw firecrackers and flares at police officers in what is seen as a major escalation of the nine-month-long protests.

Police threw multiple rounds of tear gas and charged at the demonstrators who hurled bottles, rocks and flares at them.