The EU is also considering a possible summit of all 28 EU leaders next week to assess the migration crisis.
Meanwhile, the chief of the International Federation of Red Cross and Red Crescent Societies says European countries are misguided if they think erecting fences will help solve the continent's immigration crisis.
Fresh from a trip to Hungary, Elhadj As Sy told The Associated Press on Tuesday that "we know throughout history that fences will never be a solution to anything."
Hungary has put up a fence with razor wire along its border with Serbia to block an influx of people — many from war-torn Syria — heading to the European Union. The IFRC secretary-general said he hoped European "solidarity will prevail" to help the arriving masses.