France’s National Front and Britain’s UKIP were among Eurosceptic parties to make big gains in the European Parliament elections.
Both parties, according to preliminary results, topped the vote in their respective countries.
Anti-EU parties also polled strongly in Denmark and Italy.
The trend, though, was bucked in Greece, where anti-austerity sentiment is thought to have driven radical-left party Syriza to victory.
Voter turnout is estimated to have been the same as 2009, at around 43%.
Early offical projections have put the centre-right EPP grouping ahead in the European Parliament, with 212 out of 751 seats.
But the group lost around 60 seats, compared with 2009.
But that did not stop the EPP’s nomination for the European Commission presidency, Jean-Claude Juncker, from claiming he was ‘entitled’ to the post.
One of his closest rivals, Martin Schulz, leader of the socialist grouping, refused to concede victory.
This election is the first time votes cast will have to be taken into account when choosing the next president of the European Commission.
EU leaders will now meet on Tuesday and begin negotiations with the European Parliament to choose the next EC president.
The favourite will be Juncker but he must gain a majority in the European Council and European Parliament.
One of the largest democratic events in the world, the European Parliament elections span across four days, 28 countries and almost 400 million citizens are being called to decide who they want to represent them in the European parliament for the next five years.
Re-live our election night coverage