BRUSSELS (Reuters) – Germany, Austria, Denmark and Norway should lift border controls within six months, the European Commission said on Tuesday, hours after Sweden said it was also planning to end frontier checks.

Part of the European Union’s response to a surge of refugees and migrants in 2015, the bloc allowed controls in its passport-free area, despite concerns about the impact on trade, but EU home affairs commissioner Dimitris Avramopoulos said they should now end.

“The time has come to take the last concrete steps to gradually return to a normal functioning of the Schengen area,” he said of the passport-free area named after a town in Luxembourg and meant to be a symbol of free movement in the bloc.

“Schengen is one of the greatest achievements of the European project. We must do everything to … protect it,” Avramopoulos said in a speech.

More than a million people sought asylum in Europe’s rich north in 2015, mostly in Germany but also in large numbers in Sweden, straining the capacity of countries to cope.

A contentious deal with Turkey to stop Syrian refugees from reaching Greece and the overland route to Germany, in return for EU funds, has reduced flows to a trickle, although thousands of migrants still try to reach Europe from Libya via sea routes.

The Swedish government said on Tuesday it would remove ID checks on journeys from Denmark into Sweden. However, its policy was not immediately clear after it said it would also maintain surveillance cameras and x-raying vehicles passing over the border.

Germany has argued it needs the controls despite the fall in migrants coming through Greece and the Western Balkans to combat the threat of Islamic militancy in Europe.

Under EU rules, the countries were allowed to impose the emergency controls for up to two years in September 2015.

The EU executive approved six-month extensions of controls at the German-Austrian border, at Austria’s frontiers with Slovenia and Hungary and at Danish, Swedish and Norwegian borders. Norway is a member of Schengen but not the EU.

EU governments must now agree to the recommendations.

(Reporting by Robin Emmott; editing by Francesco Guarascio)