ZAGREB, Feb. 5 (Xinhua) -- Greece will support Croatia's entry into the Schengen area as soon as possible, and next year will be crucial when Croatia assumes the EU Presidency, Greek President Prokopis Pavlopoulos said here on Tuesday as he started a two-day official visit to Croatia.

Croatian President Kolinda Grabar-Kitarovic stressed Greece's significant role in managing the migration crisis, saying it plays the role of Europe's first border guard.

"The West Balkans route is still closed, but we are calling for constant caution due to the further pressures of migrants on that route," said Grabar-Kitarovic.

The two presidents supported the further enlargement of the European Union and the need for all Western Balkan countries to enter the EU when they fulfil the conditions.

He said that the EU must be built on the federal principle and that it is a union of nations.

"Skeletons from the past are awakening and we must take measures to overcome these threats. Europe is built on the ruins of the Second World War and we have to fight to never repeat it again," said the Greek president.