The European Council President Donald Tusk has called on EU leaders to take a “sober and brutally honest” look at the bloc’s problems, in the wake of Britain’s shock vote to leave the EU.
As they gather in Bratislava for a meeting without the UK, they will discuss ways to regain trust in the EU.
The meeting is not due to discuss negotiations with Britain, but will look at the future as a bloc of 27.
Officials say Mr Tusk views migration as the main issue to tackle.
Even though Britain’s referendum result is not on the agenda, and the British Prime Minister Theresa May is not attending the summit, there is little doubt that Brexit will overshadow the meeting.
In a statement on the eve of the summit, Mr Tusk said it was true that European had been shaken “by all kinds of crises” recently, and could not act as if nothing was wrong.
“It’s my feeling that the best motto for the Bratislava meeting is that we must not let these crises go to waste,” he said.
Instead, he said, the EU should make a “realistic diagnosis of the causes of Brexit”.
The European Council leader called on EU leaders to assure citizens that they had “learned the lessons from Brexit”, and that they were are able to “bring back stability and a sense of security”.
But EU countries are deeply divided over how to bolster the economy and the Eurozone, how to safeguard European security, and how to respond to an influx of migrants.
The summit host, Slovak Prime Minister Robert Fico, is one of a group of central and eastern European leaders who object to the EU migrant quota system which distributes migrants across the EU. He has said Slovakia will not accept “one single Muslim migrant” and has mounted a legal challenge to the scheme.
On Tuesday, Luxembourg’s Foreign Minister Jean Asselborn called for Hungary to be suspended or even expelled from the European Union because of its “massive violation” of fundamental EU values, specifically the government’s treatment of refugees.
For France, the priority is border security in the wake of a number of Islamic extremist attacks in the country.
France and Germany have outlined plans to deepen European military co-operation, which were reinforced in the State of the Union address by European Commission President Jean-Claude Juncker on Wednesday, in which he called for European Military Headquarters.
Britain’s departure from the EU removes one of the biggest obstacles to stronger EU defence in tandem with Nato.
But the French President Francois Hollande also said Britain’s vote to divorce with the EU had triggered a crisis that threatened the bloc’s very existence.
“It’s not just another crisis, it might be an existential crisis”, he said on Thursday following a meeting with German chancellor Angela Merkel in Paris.
The one-day Bratislava meeting is set to be the first in a number of confidence-building meetings where a “roadmap” should be set up to culminate in a summit in March in the Italian capital Rome, when the 60th anniversary of the EU’s founding Treaty of Rome will be celebrated.