Senior politicians across Europe have voiced dismay at EU parliamentary election results, after low turnouts and big gains for opposition parties.
The disappointing turnout figures have spread gloom in Brussels
Governing parties in Germany, France and Poland suffered big losses, while many eurosceptic parties had their best result at the polls.
Dutch Foreign Minister Ben Bot said the outcome was a "disaster for the existing coalition in many countries".
Turnout reached a record low, with just 45.3% of EU voters casting ballots.
European Parliament spokesman David Harley said turnout was "pathetically low" for many of the 10 new member states, which averaged a mere 26.4%.
The lowest turnout was in Slovakia, where fewer than 17% cast their votes.
The figure was slightly higher in neighbouring Poland, where President Aleksander Kwasniewski described his country's apathy as "a disease we will have to look at". He said there was a need to analyse "why we are so far from civic values".
Outgoing European Parliament President Pat Cox described the results as a "wake-up call" and warned European leaders that they had to demonstrate the EU's relevance to voters.
"Regrettably, Europe is too absent from European elections in east and west," he said. "States need to engage, particularly in central and eastern Europe, in voter education of EU institutions."
Mr Cox said eastern and central European countries had successfully mobilised large majorities to vote in favour of EU membership in referendums last year.
"Nothing like an equivalent effort of mobilisation was made on this occasion," he said. "I think a lot of public opinion felt, 'But we voted for that last year, why are you asking us again?'"
The BBC's European affairs correspondent William Horsley says the protest vote across the EU may push the heads of government to water down some of their integrationist ambitions.
EU foreign ministers are now meeting in Luxembourg to consider revisions to the draft EU constitution, designed to make it more acceptable to eurosceptics who made a big impact in Britain and Poland.
Germany's governing Social Democrats recorded their worst result since World War II. Official results showed the party took just 21.5% of the vote, with the Christian Democrats set to be clear winners with 44.5%.
- French President Jacques Chirac's Union for the Popular Movement, with 16.6% of the vote, finished a far second behind the Socialist Party, on 28.9%, according to the final results.
- In Britain, Labour and the Conservatives both saw their vote slump. With most results in, the two main parties looked set to secure less than half of the vote between them, for the first time ever. The Tories had 27.4% and Labour 22.3%, while the eurosceptic UK Independence Party was running third with nearly 17%.
- In Poland, largest of the new EU members, partial results indicated the anti-EU League of Polish Families came second with 16.4%, while the governing left party won just 9%.
- Italian Prime Minister Silvio Berlusconi suffered a setback, with his Forza Italia party dropping to 21%, compared with 29.4% in the 2001 general elections. But partners in his centre-right coalition made modest gains.
- In Spain, the ruling Socialists appear to have bucked the trend, winning some 43.7%, while the conservatives took about 40.8 %, according to provisional results.
- With all the ballots counted in the Czech Republic, eurosceptic Civic Democrats won 30% of the vote to trounce the ruling Social Democrats, who only managed to poll 8.8%.
Voters in 19 of the 25 EU nations cast ballots on Sunday, the fourth day of elections which have already seen the other six countries complete polling for their share of the 732 MEPs.
In all, about 155 million people of some 350 milllion eligible voters in the 25 member states cast their ballots, making it one of the biggest democratic exercises in the world.
Parties of the centre-right are expected to maintain their position as the biggest single bloc in the new parliament when final results are announced.
The unprecedented apathy among voters had been feared by EU observers.
However, the BBC's Oana Lungescu in Brussels says few had predicted that turnout would be lowest not in the UK and the Netherlands, as five years ago, but in the eight central and eastern European countries that joined the EU on 1 May.
Our correspondent says this is unusual, since after previous enlargements, new members showed greater enthusiasm about European polls than voters in the old member states.
However, two of the newest - and smallest - EU members produced the highest turnouts.
Malta saw 82% of its electorate vote, while Cyprus had a participation rate of 71.2%.