EU leaders are working to defend the principle of free and unfettered travel through much of the continent, seeking to keep any reinstatement of internal national controls as a last resort.
With the euro currency under increasing pressure because of the Greek financial meltdown, the leaders are trying today to contain any crisis affecting another cornerstone of European unity created over the past quarter century.
After Italy, France and Denmark all took action over the past months to roll back the ease of visa-free continentwide travel, German chancellor Angela Merkel said the EU should cherish this "huge asset that we cannot afford to put at risk by national sensitivities."