Countries operating additional border checks within Europe's passport-free Schengen area should end them by November, the European Commission said on Tuesday.

After allowing an extension of the interim border controls several times over the past 18 months, the executive arm of the EU said it now recommended just one final half-year extension from mid-May.

EU Migration Commissioner Dimitris Avramopoulos told reporters that the controls had been "exceptional" and a "last resort."

"The time has come to take the last concrete steps to gradually return to a normal functioning of the Schengen area," he added.

Austria, Denmark, Germany, Sweden and non-EU Norway introduced the ID checks at their borders at the height of the migrant crisis when more than 1.5 million people - many of them Syrian refugees - landed in Europe and attempted to travel to its wealthier nations to seek asylum.

For several months, the surge of those seeking refuge from conflict and poverty threatened the future of the Schengen zone, where 26 European countries have abolished passport and other internal border controls.

The commission called on member states to find alternatives to border checks such as stepped-up police checks in border areas or along main routes.

The recommendation has yet to be approved by all EU states.

Sweden drops identity checks

Sweden said Tuesday it would scrap identity checks for travelers from Denmark to Sweden but tighten other border controls.

The passport checks, which will end on Thursday, were criticized by regular train commuters between both countries due to the bottlenecks created by the increased controls.

Swedish Interior Minister Anders Ygeman said the number of asylum bids had dropped sharply from about 10,000 a week in the autumn of 2015 to the less than 500 a week at present.

The Schengen area comprises 22 EU countries plus Iceland, Liechtenstein, Norway and Switzerland.

mm/jm (AFP, dpa)