Brussels (dpa) - EU member states backed measures Friday to extend border controls within Europe‘s passport-free Schengen zone for up to two years if necessitated by the migration crisis and Greece‘s difficulties in controlling its external frontiers.The European Union is contending with its largest population movements since World War II. More than 950,000 people have reached the continent this year, many fleeing war-torn Syria.Most make their way from Turkey to Greece before continuing through the western Balkans to reach wealthy northern European countries, such as Germany and Sweden, straining resources and overwhelming authorities in transit and destination countries.Germany, Austria and Sweden have all reintroduced border controls to cope with the flows of people reaching their territories, but the current provisions only permit the measure for up to six months.In the case of "serious deficiencies" that threaten the functioning of Schengen, ministers agreed to the need for a "common European framework to be able to continue controls on certain [border] segments for more than six months," said Luxembourg Foreign Minister Jean Asselborn, whose country holds the EU‘s rotating presidency.Media have reported that such a move would effectively amount to an expulsion of Greece from the Schengen zone, but Asselborn rejected this argument."It is not legally possible to exclude a state from the Schengen zone," he said.Nonetheless, Greece finally turned to the EU this week for help with the migrant arrivals on its shores - a move that Brussels has long been asking for.Athens requested emergency resources and border guard support for the Aegean islands and agreed that the EU border agency Frontex could help out at its frontier with Macedonia.The cash-strapped country has long come under fire for dragging its feet over the implementation of measures to secure its borders and register all arrivals, effectively allowing people to pass through the country unchecked.German Interior Minister Thomas De Maiziere said the rate of progress in securing Greece‘s borders was "very dissatisfactory," pointing in particular to lags in the establishment of hotspots where migrants and asylum seekers are supposed to be registered and fingerprinted."I am fighting for a European solution, but time is running out for European solutions," he warned.Last month‘s terrorist attacks in Paris drove home the need to better control those entering the EU. At least one perpetrator is believed to have reached France after registering as an asylum seeker in Greece.But French Interior Minister Bernard Cazeneuve said it was important to "bear in mind the difficulties that Greece is confronted with and help Greece to overcome these difficulties" rather than pointing fingers.Meanwhile, Asselborn said other member states also had to step up to the plate, not only by providing Athens with equipment and manpower but also by pressing ahead with the previously agreed relocation of 160,000 asylum seekers from Greece and Italy. The scheme got off to a slow start.The minister also warned against getting drawn into a debate about a German-backed scheme to potentially resettle hundreds of thousands of aslyum seekers from Turkey, warning that the idea was "illusory" and distracted from the relocation plan.The ministers also discussed plans Friday for a permanent EU border and coast guard as well as progress on a controversial permanent mechanism to relocate asylum seekers within the EU.The European Commission is expected to present proposals on both issues on December 15.