EU leaders have agreed to re-evaluate the bloc's agenda after voters "sent a strong message", European Council President Herman Van Rompuy has said.
Mr Van Rompuy said leaders of the 28 member states had asked him to launch consultations on future policies.
He was speaking after a meeting in Brussels to discuss big election gains by populist and far-right parties.
The results of the European Parliament election led to calls for an EU rethink by those leaders who suffered defeats.
But despite gains by anti-EU groups, pro-European parties still won most votes overall.
Tuesday's summit was the first opportunity for leaders of all member states to discuss the way forward after last week's polls.
A BBC correspondent says reforms could include less regulation and less focus on economic austerity policies, while measures to boost growth and create jobs could address voter discontent.
Mr Van Rompuy said the results of the European elections had shown "a mix of continuity and change" and that the Eurosceptic message from voters was "at the heart" of discussions between leaders.
He said the meeting in Brussels had been a "useful first discussion" and that EU leaders had agreed on putting the economy at the heart of the group's agenda.
"As the Union emerges from the financial crisis it needs a positive agenda of growth," he said, repeating a common refrain of what is needed to reverse growing anti-EU sentiment.
'France cannot live isolated'
President Francois Hollande asked Europe to "pay attention" to France after describing his Socialist party's defeat to the far-right National Front as "painful."
The National Front - which Germany's finance minister described as "fascist" - stormed to victory with a preliminary 25% of the vote, pushing Mr Hollande's Socialists into third place.
National Front President Marine Le Pen said she would use her electoral mandate to "defend France" and fight "crazy measures like votes for immigrants."
Speaking after EU leaders met in Brussels, Mr Hollande said the National Front victory was "traumatic for France and Europe."
"France cannot live isolated and frightened. Its destiny is in Europe," he added.
German Chancellor Angela Merkel said her country had the "utmost interest in France being successful", adding that she would do all she could to help growth and competitiveness in the French economy.
Mr Van Rompuy also told reporters that he would hold talks with the political groups to be formed in the European Parliament on who will be named to head the next Commission, the EU's executive arm.
On the latest projections, the centre-right European People's Party (EPP) will be the biggest political group and its candidate is former Luxembourg premier Jean-Claude Juncker.
The German chancellor, whose Christian Democrat party is part of the EPP, indicated Mr Juncker may not end up leading the Commission, after some member states expressed reservations about him.
UK Prime Minister David Cameron, who sees Mr Juncker as too much of an EU federalist, is among those opposed to his nomination.
EU leaders have traditionally named the Commission head on their own, but under new rules they now have "to take account" of the European election results.
The BBC's Chris Morris says the process for choosing the president of the Commission could produce fireworks amid rumblings over interpretations of the Lisbon Treaty.
But Irish Prime Minister Enda Kenny said that while there would be no time limit on Mr Van Rompuy, he would be expected to report back within two or three weeks.
"It should not be dragged out too long," Mr Kenny said.
Source: BBC