German Interior Minister Horst Seehofer has warned of a larger influx of refugees than that seen in Europe in 2015. He made the statement during an official visit to Greece, DW reports.

Traveling with incoming European Commission President Ursula von der Leyen, Seehofer also said the EU had to do more to support Turkey so that refugees did not attempt the often dangerous crossing to Greece.

“We have to help our European partners even more in patrolling the EU’s external borders; we have left them alone for too long,” Seehofer told the Bild am Sonntag newspaper, referring not only to Greece but also to Spain and Italy. “If we don’t, we will once again see a refugee wave like in 2015 — maybe even greater than four years ago.”

Seehofer said Europe had to avoid a crisis for which it was unprepared, as it had been in 2015. He clarified that he had “the full support” of Chancellor Angela Merkel, with whom he has publicly differed on refugee policy in the past.