Hundreds of riot police on Sunday separated opponents and loyalists of Serbia's autocratic President Aleksandar Vucic in central Belgrade, as political tensions boil after a year of persistent anti-government protests. 

Several thousand people faced off on both sides of the police cordon with officers in full gear as they stood in several rows between the shouting crowds who threw bottles and flares at each other.  

Tensions in Belgrade soared a day after tens of thousands of people joined a huge rally in the northern city of Novi Sad that marked the first anniversary of a train station disaster which killed 16 people.

Anti-government protesters in Belgrade gathered in support of Dijana Hrka, the mother of Stefan Hrka, one of the Novi Sad station tragedy victims.

Protesters on Sunday evening also gathered in Novi Sad and some smaller towns in support of Hrka. 

The commemoration rally on Saturday in Novi Sad also reflected major discontent with Vucic's 13-year-long increasingly authoritarian rule.

Youth-led protesters are demanding an early election they hope would oust the populist government from power.

Protesters believe rampant government corruption during renovation work on the Novi Sad station building led to negligence and disregard of the construction safety rules, and consequently to the collapse of the concrete canopy on the people standing below. 

Authorities have cracked down on protesters in recent months, with hundreds detained and police breaking up protests.

Pro-government media and officials have branded protesting university students as “terrorists,” accusing them of inciting violence.