EU member states could be flooded with refugees by Turkey, the country's President Recep Tayyip Erdogan has said.

In an Ankara speech, he has confirmed reports that he threatened EU leaders at the G20 summit in November of last year.

Greek website euro2day.gr quoted earlier this week Erdogan as telling EU Commission President Jean-Claude Juncker that Turkey could "open the doors to Greece and Bulgaria anytime and put the refugees on buses."

"I am proud of what I said. We have defended the rights of Turkey and the refugees. And we told them [the Europeans]: 'Sorry, we will open the doors and say 'goodbye' to the migrants'," AFP quotes Erdogan as saying on Thursday.

Separately, NATO said it was deploying a naval group to the Aegean Sea to combat people smuggling which has brought hundreds of thousands of migrants to the continent.

Daily Sabah also quotes Erdogan as slamming the United Nations for failing to tackle the migrant crisis and for its "insincere" approach to it, underlining Ankara's patience is wearing thin. The Turkish head of state added the UN should not be calling on Turkey to take in more refugees from Syria, but should be urging other states to receive refugees from Turkey.

The developments come days after the EU agreed on the mechanism to raise EUR 3 B that will be given to Turkey to host the 2.5 million refugees living in its camps, although many refugees are already scattered across its towns and cities.