New Delhi, Nov. 4 -- Hundreds of riot police Sunday separated opponents and loyalists of Serbia's autocratic President Aleksandar Vucic in central Belgrade as political tensions boiled after a year of persistent anti-government protests.

Several thousand people faced off on both sides of the police cordons with officers in full gear standing in several rows between the shouting crowds who threw bottles, flares and stun grenades.

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 there which killed 16 people, and triggered a youth-led movement demanding political changes, which has challenged Vucic's firm gr...