Austria said on Monday it will meet with its Balkan neighbors to discuss what action they might take if a deal with Turkey aimed at restricting the flow of illegal migrants into the European Union collapses.

Turkey has threatened to walk away from the deal agreed in March if Turks are not granted visa-free travel to the bloc, while a crackdown by President Recep Tayyip Erdogan since a failed coup attempt in July has discomfited European leaders.

"Very significant cracks are apparent in this deal between Europe and Turkey and we simply have to prepare for what will happen if this deal no longer holds," Austrian Defense Minister Hans Peter Doskozil told a news conference after a meeting of his counterparts and other defense officials from the region.