BRUSSELS (AP) — The European Union's executive on Wednesday announced an extraordinary mini-summit of EU and Balkan leaders this coming Sunday to deal with the migrant crisis.

A statement from EU Commission President Jean-Claude Juncker's office said "there is a need for much greater cooperation, more extensive consultation and immediate operational action."

Nations invited to attend are EU member states Austria, Bulgaria, Croatia, Germany, Greece, Hungary, Romania and Slovenia, as well as non-EU countries Macedonia and Serbia.

The announcement came as migrants from the Middle East and Africa continue to make their way across Europe by the tens of thousands, fleeing war or seeking a better life. Many of the arrivals attempt to enter the EU through the Balkans.

The statement from Juncker's office said the extraordinary meeting of heads of state and government is necessary because of "the unfolding emergency in the countries along the Western Balkans migratory route."

"The objective of the meeting will be to agree common operational conclusions which could be immediately implemented," the EU Commission statement said.

It said officials from the U.N. High Commissioner for Refugees have also been invited to attend, as well as officials from the EU's own border protection agency and asylum office.

More than 20,000 migrants have entered Slovenia since Saturday when the refugee route toward Western Europe switched toward the Alpine nation. Dozens of migrants, including women and small children, forded a river in the cold of the night while crossing from Croatia to Slovenia.