French President Francois Hollande and German Chancellor Angela Merkel on Thursday pressed European partners to set an agenda of reforms to overcome difficulties that Brexit has triggered.
"What we want is to face the causes which had led UK leave. What we must have in mind is to give to the Europeans a clear view of what will be their future," Hollande said in a joint press meeting with Merkel.
With that aim, the French president called for a roadmap of reforms at the informal EU summit whose "first priority is security ... our border security, our security against external threats."
On the eve of the EU gathering in Bratislava, Merkel, on her visit to Paris, expressed "a real willingness to move forward".
"It is now about applying an agenda for Bratislava that makes clear we are determined to react together to the weaknesses, to the tasks we face," she added.
On Friday, European leaders will meet in the Slovak capital, the first meeting since Britain quit the European Union. They will discuss ways to better handle immigrant flows, boost growth and create more jobs for youth.