Most EU member states vote on Sunday in elections to choose new members of the European Parliament.
Voting began on Thursday, but 21 countries, including Germany, France, Poland and Spain, will hold elections on Sunday.
Austria, Belgium, Bulgaria, Croatia, Cyprus, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Lithuania , Luxembourg, Poland, Portugal, Romania, Slovenia, Spain and Sweden all vote on Sunday. Italy will also have a second-day of voting.
The European Parliament has said it will issue an EU-wide exit poll at around 2030 CEST (1830 GMT) and a first provisional result after 2300 CEST when the final EU votes in Italy have been cast.
Voter turnout in 2019, at the second-largest democratic election in the world after India, was around just 50%.
Higher voter turnout is projected for the 2024 vote, according to a poll conducted earlier this year in which 60% of voters said they were interested in the election.
Opinion polls predict a surge in support for hard and far-right parties.
Many voters have been hit by the cost of living crisis, have concerns about migration and the cost of the green transition and are disturbed by rising geopolitical tensions, including the war in Ukraine.