PARIS-  One of Greece's closet allies – French President Emmanuel Macron – said the European Union would be making a big mistake unless serious sanctions are brought against Turkey for planning to send energy research ships off Greek islands.

The EU has issued only soft sanctions for Turkish drilling off Cyprus, apparently emboldening Turkish President Recep Tayyip Erdogan to forge ahead with drilling plans off the Greek islands of Crete, Rhodes and Karpathos.

That has set the Greek military on high alert amid fears a shooting conflict could break out if a Turkish research vessel enters Greek waters, with Prime Minister Kyriakos Mitsotakis saying there would be a response.

The EU has been timid with Erdogan, reluctant to confront him for fears he will flood the bloc with more refugees and migrants through Greece's land border and allowing human traffickers to send more to Greek islands.

Turkey is supposed to contain some 3.3 million people who went there fleeing war and strife in their homelands but allows traffickers to keep sending more to five already overwhelmed Greek islands near the Turkish coast.

At a meeting of EU leaders in Brussels, Mitsotakis also asked for sanctions but no action was taken and European Council President Charles Michel indicated the bloc should go easy on Erdogan and offered only talks sometime later.

“In this part of the Mediterranean, which is vital for our two countries, energy and security issues are essential. What's at stake is a power struggle in particular of Turkey and Russia which are asserting themselves more and more and in the face of which the EU is still doing too little," Macron told reporters alongside Cypriot President Nicos Anastasiades, said the news agency Reuters.

"It would be a serious mistake to leave our security in the Mediterranean in the hands of other actors. This is not an option for Europe and it is not something that France will let happen,” he said, with the French energy giant Total licensed to drill off Cyprus.