He added that the meeting reaffirmed the determination not to allow illegal migration any more.

"Our common conclusion was that we must do more to prevent a reopening of the Balkan migration route for illegal migrations," Cerar said after the meeting of 11 European countries along the route, from Greece to Germany.

He said that the countries must work together to strengthen controls at the EU's external borders, and to do everything possible for the implementation of the EU-Turkey agreement on the return of illegal migrants.

"The awareness has been reaffirmed that we are not going to allow illegal migrations any more, and based on that measures will be taken at the bilateral level, in cooperation between the countries, as well as in coordination from Germany via Slovenia to Greece."

The leaders expect Greece to make an additional effort to better implement the return of migrants as agreed. "I believe there will be a meeting in Greece in the coming days between EU and German officials and the Greek authorities in charge," to find extra funds and resources to make the agreement work better.

Cerar emphasized that German Chancellor Angela Merkel too understood the need for a joint action to secure the EU's external borders against illegal migrations. "We all agreed on that today, and Merkel explicitly underscored as well that Greece was not doing enough in that sense."

The German chancellor offered concrete assistance to Greece, while Cerar said that joint assistance should also be provided to Bulgaria, Macedonia, Serbia, Italy and other countries in case of pressures.

Cerar expects for the European Border and Coast Guard to become operational as of October and that by the end of the year the force will arrive in the countries in need of assistance.

"Slovenia will contribute its share and already has; our police officers already are in other countries on external borders of the EU, and we will deploy more, as well as equipment," he said, urging other countries and the EU to send police, equipment and to provide financial aid.

"If we prevent illegal migration on the EU's external borders, we will also prevent conflicts which in the event of a new wave would definitely emerge not only in the most sensitive region of the Western Balkans but possibly also between EU member states."

Cerar also insisted that border closures were unacceptable, in particular within the Schengen passport-free area.

Commenting on Hungarian Prime Minister Viktor Orban's call for the immigrants to be sent to an island outside of the EU, Cerar said that such radical statements were "unacceptable".

"We need to put up in place a comprehensive approach to migrations. The refugees fleeing from hot spots out of fear for their lives must be accepted in an organised fashion and accommodated on the principle of solidarity."

"Slovenia is a model of solidarity, we are accepting monthly certain numbers of refugees from Italy, Greece, as well as Turkey. The numbers are such that we can handle, so that we can integrate these people and suitably take care of them. Other countries need to follow suit."

But Cerar repeated that illegal migrations and smugglers at the EU's external borders must be stopped and that the EU must do much more to tackle the root causes of crises at hot spots.

Cerar today briefly discussed Austria's measures with Chancellor Christian Kern. He said that if Austria stepped up control at its border, so would Slovenia, and that the same held true for other, even more radical measures.