EU leaders were crafting a new vision Friday for the future of their bloc at "honest and frank" talks in Bratislava about the causes of public disillusionment and Britain's shock decision to withdraw.
"We are in a critical situation," German Chancellor Angela Merkel said as she arrived for the talks in the Slovakian capital. "This is about showing through deeds that we can become better."
Officials say the Brexit vote has highlighted how much trust citizens have lost in the EU and that to regain it, the bloc has to overcome its divisions and more convincingly address its population's main concerns.
"The discussion today has been honest and frank ... but without attacks," an EU official said Friday on condition of anonymity, describing the atmosphere around the table as "good."
The 27 leaders, who were meeting without Britain's Theresa May, were asked to craft priorities around the themes of migration, terrorism and globalization - areas that European Council President Donald Tusk, who is chairing the informal summit, has identified as EU citizens' top concerns.
"We haven't come to Bratislava to comfort each other," Tusk said.
"If we talk about nothing and stonewall ... it's useless for us to be here," Luxembourg Prime Minister Xavier Bettel added.
The idea is for the leaders to help produce a "Bratislava roadmap" of actions to be taken over the six months that will lead in March to the 60th anniversary of the Treaty of Rome, an EU founding pact.
This could include steps to double an EU investment fund, improve external border security and boost defence cooperation, according to a draft paper prepared for the summit by the European Commission, seen by dpa.
Germany and France have been fuelling a new push for stepped-up military cooperation in the EU - long a taboo subject because of British resistance.
Concrete areas of cooperation could include setting up a single headquarters for EU civilian and military missions. But some member states are still cautious on the issue.
Both the leaders of Lithuania and Sweden warned Friday against the idea of going as far as creating a European army, amid concerns that such a project could duplicate the work already being done by NATO.
On the migration front, a "large majority" of leaders have pledged to deploy guards and equipment to the border between Bulgaria and Turkey, as part of efforts to clamp down on migrant flows, the EU official said.
Leaders agree on the "absolute need to regain control of the [EU's] external borders," he added.
Meanwhile, the so-called Visegrad group of four central European countries called in a statement for "flexible solidarity" in response to migration, noting that any scheme to distribute refugees across the bloc should be "voluntary."
Whatever priorities are identified, the leaders are expected to work on them at their upcoming regular summits in Brussels, but also during another informal summit in Malta before their Rome meeting.
Belgian Prime Minister Charles Michel spoke Friday of the need to "re-boost Europe," but Austrian Chancellor Christian Kern warned against expecting "big revolutions."
Little discussion is expected on the subject of Brexit, which leaders will touch upon during a boat ride along the Danube, the source said. EU officials insist that negotiations cannot begin until Britain formally notifies its intention to leave.