The EU said on Tuesday it was concerned about the situation on the route that migrants are taking through the west Balkans and is making plans to deal with a possible humanitarian crisis.

"We are concerned about the developments along the Balkan route and the humanitarian crisis that might unfold in certain countries especially in Greece," EU migration commissioner Dimitris Avramopoulos and Dutch Dutch migration minister Klaas Dijkhoff, whose country holds the rotating EU presidency, said in a statement.