EU trade ministers on Friday gave the green light to Austria, Germany, Denmark, Sweden and Norway - all members of the visa-free Schengen zone - to extend temporary border controls for three months.

Schengen allows passport-free travel across 26 countries without border checks, but last year's influx of more than 1 million migrants raised concerns about security, especially along the so-called Balkan route from Greece to northern and Western Europe.

Balkan countries and Austria closed down the route in mid-February, but fears have persisted that Greek authorities, overwhelmed by crowded refugee camps and a fragile finances, are ill-equipped to control Schengen's external frontier.

The EU recommended on May 12 that the five Schengen countries could continue to enforce temporary border controls for a maximum of six months for ‘exceptional circumstances.’  Berlin, Vienna and Copenhagen had all called for an extension of border controls beyond a November 12 deadline, and several European states initially criticized the move, arguing that migration pressures have dropped off.

 In allowing the three-month extension of border checks and controls, the EU said the measures should be ‘targeted and limited in scope, frequency, location and time, to what is strictly necessary.’   Greece and Hungary voted against the move, with Athens saying the extension recommendation was based on speculation.

 Greece said in a statement that its border check points had been tightened since November 2015 and the country had taken measures to prevent and deter migrant movement from its mainland to the north.

Bulgaria and Cyprus abstained.

Sweden announced earlier Friday it was extending border checks until February.