Seven out of 26 Schengen countries have emergency border controls in place, including Germany. On Friday, the Commission said it wanted them all lifted no later than December.

Under the Schengen agreement, 26 countries allow passport-free travel without border checks. But seven of those have re-introduced internal border controls since September in to help stem the most significant migration flows Europe has seen in decades.

Open internal borders are seen as a major achievement of European integration that improved travel, tourism, trade and supply chains across the bloc, boosting growth.

But the commission's plan also calls for a new European border and coast guard to start operating in the summer to secure the bloc's external borders. Overwhelmed Greece is to receive more support in securing its border with Turkey.

EU Commissioner Dimitris Avramopolous, who presented the plan on Friday, said managing Europe's borders was essential.

The Commission warned that the border checks introduced by Austria, Belgium, Denmark, Germany, Norway and Sweden could cost the bloc's economy up to 18 billion euros ($19.7 billion) due to higher costs for the transport of goods by road. Workers would lose time crossing borders and tourists could be discouraged from traveling within Europe, the Commission predicted.

The EU is scrambling to come up with a plan to manage the influx of migrants, mainly from Syria, Afghanistan and Iraq. So far this year, more than 135,000 arrived in Europe - mostly through Greece - after more than a million people entered the bloc in 2015.

The Commission's announcement comes ahead of an EU summit with Turkey on March 7, which is aimed at finding ways to deal with migrants crossing into the EU via Turkey.

ng/kms (Reuters, dpa)