A man casts his vote in the European Parliament Elections, during the Belgian general and regional elections and European Parliament Elections, in Limal, Belgium, May 26, 2019.
A man casts his vote in the European Parliament Elections, during the Belgian general and regional elections and European Parliament Elections, in Limal, Belgium, May 26, 2019.

Voters in 21 European nations streamed to the polls Sunday in the final day of pivotal elections for the European Union parliament, a continent-wide referendum pitting nationalist and populist candidates against those calling for tighter EU unity.

The four days of voting began Thursday across the 28-nation EU, with 426 million people eligible to vote in contests for the 751-member legislature. The elections are considered the most important since 1979, when the first international vote was held for the EU parliament.

In the current vote, right-wing nationalists are hoping to elect candidates to reshape EU policies to slash immigration into Europe and are expected to make gains, although mainstream parties are expected to retain power in the assembly that sits in both Brussels and Strasbourg.

One anti-migrant, hard-line nationalist, Italy's Interior Minister Matteo Salvini, said that he was sensing a "change in the air" and that a victory by his right-wing League party would "change everything in Europe."

"We need to do everything that is right to free this country, this continent, from the illegal occupation organized by Brussels,'' Salvini told a rally in Milan last weekend that was attended by the leaders of 11 nationalist parties.

Geert Wilders, leader of Dutch party PVV (Party fo
Geert Wilders, leader of Dutch party PVV (Party for Freedom), Italy's Deputy Prime Minister Matteo Salvini, Marine Le Pen, leader of French National Rally party attend a major rally of European nationalist and far-right parties in Milan, May 18, 2019.

By late Sunday, exit polls in Germany and Greece showed that centrist governing parties would lose seats in the new formation of the continent-wide parliament.

The exit poll in Germany showed the environmental-based Green Party gaining ground, finishing in second place behind Chancellor Angela Merkel's conservatives and ahead of the center-left Social Democrats. Merkel's Christian Democrats and the Social Democrats slumped from their 2014 standing, with the far right also expected to gain seats.

"I don't want to see a right-populist Europe (that) wants to destroy the idea of togetherness," said Germany's Manfred Weber, the lead candidate of the Christian Democrat center-right European People's Party that currently is the biggest in the legislature.  
 
French President Emmanuel Macron has called for closer ties throughout the continent, even as Britain struggles to leave the EU. He has said that the EU "is facing an existential risk" from nationalists trying to divide the bloc.
 
Projections released last month by the European Parliament show the center-right EPP bloc losing 37 of its 217 seats and the center-left S&D group dropping from 186 seats to 149. On the far right flank, the Europe of Nations and Freedom group is predicted to increase its bloc from 37 to 62 seats.
 
The last polls close late Sunday in Italy but the European Parliament plans to begin issuing estimates and projections hours earlier with the first official projection of the makeup of the new parliament shortly after all polls have closed.

EU leaders are meeting Tuesday to begin selecting candidates for the top jobs at the EU's headquarters in Brussels.
 
Current European lawmakers' terms end July 1, with the new parliament taking over the following day.