EU leaders have agreed to produce a "road map" of plans within six months to regain citizens' trust in the wake of Britain's decision to leave the bloc and sharp divisions over a policy for migrants.
German Chancellor Angela Merkel said during the EU summit in the Slovak capital, Bratislava, that the British vote, known as Brexit, had plunged the rest of the 28-member EU into a "critical" situation.
"We have agreed that Europe, in the critical situation it's in after the referendum in Britain but also due to other problems we have, that we must jointly agree on an agenda, that we must have a working plan," she said.
French President Francois Hollande said that "France and Germany will continue to work so that we can deliver concrete measures [for the EU]."
EU leaders -- who met without a representative from Britain -- will meet again in the Italian capital for a summit marking 60 years since the signing of the Treaty of Rome.
Hungarian Prime Minister Viktor Orban said after the summit that it had failed to change EU immigration policies that he called "self-destructive and naive."
"Even now people were still speaking more about speeding up the distribution [of refugees] than stopping migrants at the Schengen [external] borders," he said.
Orban said he would push for changes to refugee policies at a meeting of Balkan states on September 24.
Some EU countries -- particularly Germany, Austria, and Sweden -- are upset with the lack of cooperation on the part of Eastern European countries in helping to take in the more than 1 million refugees that have come to Europe in the past 18 months.
Italian Prime Minister Matteo Renzi said in a tweet after the summit that there was "too little" progress made in Bratislava and warned that "without changing policy on the economy and immigration, Europe risks a lot."
Donald Tusk, the European Council president, said EU officials are ready to start discussing Britain's exit from the bloc "tomorrow" if necessary.
But British Prime Minister Theresa May has yet to open formal talks on Brexit.
"We want to have very good, very close relations with the U.K. At the same time, it is not possible for these [Brexit] negotiations to damage our interests," European Commission chief Jean-Claude Juncker said.
It is not known when Britain will begin negotiations on leaving the EU.
With reporting by Reuters and dpa