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.

Russia's foreign ministry shores up the beleaguered president, saying it won't 'remain unresponsive' to Serbia's protests.

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.