Updated

Several hundred mostly young people have gathered in downtown Belgrade and other Serbian cities to protest against powerful leader Aleksandar Vucic's presidential election victory.

Blowing whistles and chanting slogans against Prime Minister Vucic, the crowd in Belgrade stopped traffic in front of the parliament building on Tuesday.

The protesters have for the second day gathered after calls on social media to rally against his "dictatorship."

Vucic won the Sunday vote by a landslide against a string of fractured opposition candidates.

The opposition has claimed major election irregularities, including muzzling of the media, intimidation and bribing voters.

They are chanting "We don't want you Vucic!" and "Vucic is a thief!" A banner in Belgrade read: "The power of people is stronger than the people in power."