Greece calls on NATO as Erdogan threatens to flood Europe with millions of migrants (VIDEO)

President Recep Tayyip Erdogan has threatened the European Union his government would open the gates to millions of refugees to head to Europe if they criticised Turkey's military offensive in Syria.

The President has warned he will send 3.6 million Syrian refugees to Europe in retaliation for the worldwide criticism of his military operation.

At least 24 people have been killed, including 16 Kurdish fighters and eight civilians, while dozens more have been injured.

Lashing out at the European Union, the United States, NATO, and others that joined the condemnation, President Recep Tayyip Erdogan warned he would “open the gates” if anyone called his offensive “an invasion”.

"Hey EU, pull yourself together. I say it again. If you try to frame our operation as an invasion, our task is simple: we will open the doors and send 3.6 million migrants to you," Erdogan said in a speech to parliament.

Turkey launched an operation into Syrian territory on Wednesday, aimed at combating Kurdish militants.

Erdogan claims 109 "terrorists" had been killed so far in the operation.

Greece’s Prime Minister Kyriakos Mitsotakis on Thursday called on NATO to increase naval patrols in the Aegean after the threat by Turkey to allow more migrants to cross into Greece was made.

"I asked the secretary-general and the alliance, and member states to strengthen their presence in the Aegean Sea with more ships," Mitsotakis said after talks with NATO chief Jens Stoltenberg.

"We ask for the mission to be expanded to the south Aegean so we can cover the full scope of our country's maritime borders," Mitsotakis announced, adding that he would raise the issue at a NATO summit in December.

There are officially some 70,000 migrants and refugees in Greece and over 800 continue to arrive daily, placing pressure on already overcrowded camps on the Greek islands.

NATO currently has six ships on patrol in the northern Aegean that track the movement of incoming migrant boats and alert the coastguards of Greece and Turkey, in addition to EU border force Frontex.

Stoltenberg said he has already called on allies to provide more ships, but that any additional commitment requires a consensus between NATO members.

*Watch the video here-