More than 400 million voters are eligible to elect 751 lawmakers to the European Parliament
Dublin (AFP) - Irish voters cast ballots Friday as part of phased EU-wide elections after a campaign dominated by concerns over neighbouring Britain's messy bid to leave the bloc.
Eurosceptics are hoping for strong results across the continent but their momentum took an early hit after a Dutch exit poll on Thursday suggested pro-EU parties are headed for a surprise win there.
The Netherlands and Britain, where Prime Minister Theresa May finally announced her departure following a months-long Brexit crisis, on Thursday kicked off four days of voting for the new European Parliament.
More than 400 million people are eligible to elect 751 MEPs, with the first official results to be announced late Sunday once voting in all 28 member states has been completed.
The Czech Republic was also starting two days of voting on Friday, but most countries go the the polls on Sunday.
Britain was never meant to take part in the elections but May was forced to delay the planned Brexit date of March 29 after parliament refused to approve her divorce deal.
The Brexit Party, which was only set up this year by veteran eurosceptic Nigel Farage, is expected to score a resounding victory in Britain's vote.
The anticipated success of the Brexit Party, polling at around 35 percent, is emblematic of rising anti-establishment forces across Europe.
Around the continent, pro-European leaders are scrambling to mobilise their supporters to resist the populist surge, with opinion polls indicating nationalist parties lead in France, Italy and Hungary, among others.
They fear a good showing for the eurosceptics will disrupt Brussels decision-making and threaten reform efforts for closer integration.
Such concerns were reflected among Irish voters.
"The rise of anti-Europeanism, and the right is quite frightening in some parts of Europe, so I am voting to support Europe," said Fiona Corbett outside a Dublin polling station.
"I think that being part of Europe has been mutually beneficial."
Dublin voter Joseph O'Brien told AFP: "Europe is facing a lot of issues today.
"What I am expecting from the MEPs is to work together to further Irish interests in the EU, and being part of the European community," he said.
- 'It's been disgraceful' -
In Britain, supporters and opponents of Brexit have voiced their anger at the government in the run-up to the polls.
The country is still deeply divided three years after a referendum in which it voted to leave the bloc.
"It's been disgraceful the way the government has gone on," said Brexit Party voter Chris Fetherstone, 73, in the northern English town of Middlesbrough.
"What Theresa May has said, about leaving, she's never meant it."
Elsewhere in Europe, other eurosceptic forces are hoping for a strong showing.
Matteo Salvini of Italy's anti-immigrant League and Marine Le Pen of France's far-right National Rally (RN) want their Europe of Nations and Freedom (ENF) group to become the third largest in Brussels. The League has topped opinion polls in Italy.
Le Pen wants to strike a blow to Emmanuel Macron's faltering French presidency by overtaking his centrist, pro-European party Republic on the Move (LREM).
Polls give her RN party a slight edge, with around 23 percent support.
- Pro-EU resistance -
The strong showing by eurosceptics is not expected to sweep the whole bloc, with voters from Spain to the former Soviet Baltic states indicating solid backing for the EU.
In Germany, surveys put Chancellor Angela Merkel's CDU party -- a heavyweight in the EU-wide centre-right EPP group -- in first place, with the Greens second.
In Ireland, the Brexit crisis has been the key issue due to the future of the border with the British-ruled province of Northern Ireland, a key sticking point in negotiations between London and Brussels.
Most mainstream parties in Ireland have campaigned heavily on cementing its place in the European project.
MEP hopefuls also pledged to dampen the economic shock predicted to radiate into Ireland as a result of its largest trading partner leaving the bloc.