Anti-corruption protesters in Serbia set fire to the Valjevo offices of the country's ruling political party, city leaders said, amid clashes sparked by the deadly collapse of a rail station in November.

The offices of the the ruling Serbian Progressive Party (SNS) have been set on fire during a fifth night of unrest in a row that saw fresh clashes between anti-government protesters and riot police.

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.