Serbian police on Saturday evening clashed with anti-government protesters demanding snap elections and an end to the 12-year rule of President Aleksandar Vucic.

Police deployed scores of officers around government buildings, parliament and nearby Pionirski Park, where throngs of Vucic's backers from across the country gathered in a counter-protest.

After the protest ended at around 10 p.m. (2000 GMT) some protesters who wanted to confront Vucic's backers threw flares at police, while the police used pepper spray to disperse them.

Months of protests across the country, including university shutdowns, have been ongoing against Vucic’s rule, whose second term ends in 2027, when there are also parliamentary elections scheduled.

Vucic's opponents accuse him and his allies of ties to organised crime, violence against rivals and curbing media freedoms, something they deny.

The student protest was set to last until 9 p.m. (1900 GMT) at Slavija Square and Nemanjina Avenue, where most of the government offices are located.

Vucic has previously refused snap elections. His Progressive Party-led coalition holds 156 of 250 parliamentary seats.

On Saturday, Vucic said unspecified "foreign powers" were behind the protest. He said police should be restrained, but warned that violence will not be tolerated.

In the days ahead of the protest, police arrested about a dozen anti-government activists, charging them with undermining the constitution and terrorism. All denied the charges.

Protests began last December after 16 people died on November 1 in a Novi Sad railway station roof collapse. Protesters blame corruption for the disaster.