Austria's foreign minister says the route leading through Italy to central Europe also will need to be blocked to migrants after his country's decisions triggered the closure of the Balkan route.

Austria's cap on migrant admissions set off a domino effect of border closures across the Balkans, stranding thousands of migrants at borders. But Austrian officials say they still need to be vigilant in case migrants seek alternative routes.

Foreign Minister Sebastian Kurz told Sunday's newspaper Bild am Sonntag newspaper that "smuggling can't be prevented entirely."

Because of that, he said, "we will have to do everything that we are now doing on the western Balkan route along the Italy-Mediterranean route too." He says "the time of waving through refugees to central Europe is over, no matter on what route."