Greece must do more to adequately secure its outer borders, the European Union said Tuesday, upping the pressure on Athens amid concerns over new controls within the Schengen area.
One of Europe's most-cherished achievements, Schengen usually is the epitome of free movement, with 26 countries allowing free travel across their bloc without the need for passports or border checks.
But some Schengen nations have re-introduced internal border controls to stem migration flows, after the arrival of hundreds of thousands of migrants and asylum seekers overwhelmed their systems.
Greece had been accused of letting migrants pass through largely unchecked until countries further north shut down their borders. Unannounced EU inspections in November found "serious deficiencies" in Greece, whose border with Turkey is an external Schengen frontier.
The EU has given Athens until May 12 to fix the problems. Its executive, the European Commission, will otherwise propose that intra-Schengen border controls be allowed to continue for up to two years - a move that some observers speculate would effectively exclude Greece from the free-travel zone.
In an interim assessment issued Tuesday, the commission found that Greece had made "significant progress," but also warned that "further improvements to [Greece's] action plan and its implementation are needed in order to comprehensively address the deficiencies."
Athens still needs to provide timetables for its plans, spell out which authorities are responsible for implementing them and better use EU aid, the commission said.
"The EU's ability to maintain an area free of internal border controls depends on our ability to effectively manage our external borders," EU Migration Commissioner Dimitris Avramopoulos warned.
The commission has tried to take pressure off Greece by awarding it emergency aid and redistributing some of its asylum seekers to other member states. But the programme has had limited success, with only 615 relocated out of the country so far.
Within Schengen, migration-related border controls are currently active in Austria, Belgium, Denmark, Germany, Norway and Sweden. They hamper the free movement of people and goods in Europe, generate economic costs and have fuelled speculation that Schengen may eventually break apart.
Austria has met resistance in Brussels with plans to also introduce border controls on a key mountain pass to Italy.
"The commission is very concerned," spokeswoman Natasha Bertaud said on Tuesday. "The Brenner pass is essential for the freedom of movement within the EU."
But Austrian Chancellor Werner Faymann said that as long as border protection at the EU's external frontiers is not secured, it is "politically necessary and right for Austria to take the right steps."
He hinted at early June as the starting date for controls at the Brenner pass, which lies on one of Europe's busiest transport routes.
A police spokesman in Tyrol province told dpa on Tuesday that preparations were underway, with workers building a roof over the section of road where vehicles will be stopped and searched.
The commission will assess the "necessity and the proportionality" of any measures taken by Vienna, Bertaud said.
There has been an increase in the numbers of people reaching Italy, with more than 15,000 people arriving by sea from Libya since the beginning of March, Bertaud said, while also adding that there is "no evidence" that migration flows are shifting from Greece to Italy.