Polish Prime Minister Donald Tusk announced Tuesday that his country will introduce temporary border controls with Germany and Lithuania, raising questions about the future of free movement of people between European nations.

Mr. Tusk said the new controls will go into effect on July 7, citing increased illegal immigration as the main reason for reinstating border controls.

“We consider the temporary reintroduction of controls necessary to reduce the uncontrolled flows of migrants across the Polish-German border to a minimum,” Mr. Tusk said Tuesday.

Poland, Germany and Lithuania help comprise the Schengen Area, a zone of 29 European countries that have ended internal border controls and allow people to move freely without passports.

Mr. Tusk’s decision to resume border controls comes amid increasing scrutiny from Polish conservatives over the liberal government’s handling of immigration. While the Tusk government asserts that the overall number of immigrants Poland has accepted from Germany and Lithuania has been limited, conservatives argue that the limited border controls are a threat to the country’s security.

Other European countries have also taken steps to increase border security amid the war in Ukraine, which has created millions of refugees since 2022. In February, German Chancellor Friedrich Merz announced that he would extend temporary border restrictions for its border.

This week, Mr. Merz defended his decision to limit the Schengen Area, saying the zone can only work if it is not abused by criminals.

“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,” the Germany chancellor said Tuesday.

Mr. Merz said that he and his interior ministers have been collaborating with the Tusk government to curb illegal immigration in both directions.

• Vaughn Cockayne can be reached at vcockayne@washingtontimes.com.