Polls have opened in Serbia's general election that is seen as a test of Prime Minister Aleksandar Vucic's proclaimed bid to lead the Balkan nation to European Union membership.

Vucic has called the vote two years early, saying he needs a new mandate to press ahead with reforms demanded by the EU.

The vote Sunday comes amid a surge in popularity of far-right groups that want Serbia to ditch its EU bid and turn to Russia instead.

Vucic's Serbian Progressive Party is slated to win most votes, but the election is also expected to bring back the far-right Radical Party to Parliament after its leader Vojislav Seselj was acquitted of war crimes by a U.N. Court.

There are 6.7 million voters.