Pivotal elections for the European Union parliament reached their climax Sunday as the last 21 nations went to the polls, with results to be announced in the evening in a vote that boils down to a continent-wide battle between euroskeptic populists and proponents of closer EU unity.

Right-wing nationalists who want to slash immigration into Europe and return power to national governments are expected to make gains, though mainstream parties are tipped to hold onto power in the 751-seat legislature that sits in both Brussels and Strasbourg.

Leading the challenge to the established order is Italy’s hard-line interior minister, Matteo Salvini, head of the League party, who is assembling a group of like-minded parties from across Europe.