Poland will introduce temporary controls on its borders with Germany and Lithuania as of July 7, Prime Minister Donald Tusk said Tuesday.

The move follows rising tension over illegal migration within the European free travel zone.

Tusk warned on Monday that his country would reimpose checks on the Polish-German border if it found that Germany was sending irregular migrants to Poland, Lithuanian media reported. He also said his country would take measures to prevent illegal border crossings from the Lithuanian side, as Poland had “a lot of effort, money, sweat and, unfortunately, some blood, to make the eastern border with Belarus air-tight.”

German Chancellor Friedrich Merz on Tuesday defended Germany’s border checks. “We naturally want to preserve this Schengen area, but freedom of movement in the Schengen area will only work in the long term if it is not abused by those who promote irregular migration, in particular by smuggling migrants,” he said.

The interior ministers of Germany and Poland had discussed the situation during a lengthy phone call on Monday evening, Merz said in Berlin.

“We are also talking to the Polish government about joint controls in the respective border hinterland,” the chancellor said.

In response to Polish media reports, Merz said he wanted to clarify that Berlin did not push back asylum seekers who had already arrived. “Some people here are claiming that there is, so to speak, regular repatriation tourism from Germany to Poland … That is not the case,” he said.

This story is being updated.