Italy will close its airports to unauthorised planes carrying migrants from Germany, Interior Minister Matteo Salvini said, stirring up a dispute between the EU members over responsibility for illegals, who apply for asylum.

The two countries have been working on a deal under which Germany would send back to Italy migrants who have already applied for asylum there, but the accord has yet to be signed.

Italian daily La Repubblica reported Germany‘s refugee agency had sent “dozens of letters” to migrants advising them of a planned transfer back to Italy, possibly via charter flights. The first transfer is planned for October, 9.

“If someone, in Berlin or Brussels, thinks of dumping dozens of immigrants in Italy via unauthorized charter flights, they should know that there is not and there will be no airport available,” Salvini said in a statement published on his Twitter microblog.