Partial results from the European Parliament elections suggest that far-right parties have scored considerable gains.
In France, Marine Le Pen's National Rally party edged ahead of the centrist alliance of President Emmanuel Macron.
In Italy, exit polls showed Matteo Salvini's anti-migrant League party won the most votes in Sunday's European elections in Italy with 27-31 percent, marking a historic success for the far-right.
The leader of the far-right Sweden Democrats Jimmie Akesson celebrated with supporters at an election event in Stockholm as early results show gains for his party in the European vote.
Meanwhile, Dutch far-right leader Geert Wilders looked set to be kicked out of the European Parliament as results confirmed a win for the social democrats.
The center-right People's Party (OeVP) of Austrian Chancellor Sebastian Kurz is also on course for gains in the European elections, with the far-right Freedom Party coming third, according to a media forecast published
Official results in Slovakia showed Progressive Slovakia/Together coalition have won EU election in Slovakia with 20.1 percent of the vote, Smer second at 15.7 percent and far-right People's Party third at 12.1 percent.
Over 400 million Europeans were eligible to cast their ballots in the 28 EU member states. The battle this year is mainly between the nationalist right and pro-EU forces.
Polls opened at 7 a.m. (0400 GMT) in the east of the bloc on Sunday and was closed until midnight.
The voters chose 751 members of the European parliament for the next five years. Seven states had earlier voted, and 21 others joined them on Sunday.
Polls suggest the vote will produce a more fragmented parliament than ever, putting a potential brake on collective action in economic and foreign policy.
It was earlier predicted that the two center-right and center-left groups that have dominated Europe’s politics would lose their joint majority for the first time, and nationalist and populist forces would make gains.