Voters in 21 of the European Union's 28 member states are called upon to vote Sunday on the final day of elections for the bloc's next parliament, with initial results from four days of polling due late in the evening, dpa reported. Across the bloc, around 400 million people can elect the 751 members of the European Parliament, however there are fears that the polls could be marred by low turnout and an anti-EU backlash. In a novelty aimed at boosting voter interest, European political parties have united behind five lead candidates for the post of next president of the European Commission. The EU's executive proposes laws and plays an important role in making sure they are respected. The contenders for the two largest parties are former Luxembourg prime minister Jean-Claude Juncker for the centre-right European People's Party, and current European Parliament President Martin Schulz for the Party of European Socialists. The other lead candidates are former Belgian prime minister Guy Verhofstadt for the Liberals; Greek opposition leader Alexis Tsipras for the far-left; and a double head for the Greens - France's Jose Bove and Germany's Franziska Keller, both EU parliamentarians.