The EU on Monday said it was concerned about naval manoeuvres in the eastern Mediterranean as Turkey resumed its energy exploration work in the area.
“They will not contribute to finding any solutions," EU policy chief Josep Borell said. "On the contrary, they will lead to a greater antagonism and distrust.
“The present course of action will not serve the interests of the European Union of Turkey. We have to work together for security in the Mediterranean."
Turkey has restarted its contentious drilling and exploration work in the eastern Mediterranean.
Turkish Energy Minister Fatih Donmez on Monday said a Turkish research vessel had resumed operations in the region.
"The seismic research ship Oruc Reis, which was anchored in Antalya for its new mission in the Mediterranean, has arrived in the area where it will operate," he said on Twitter.
"Our efforts in the Mediterranean and the Black Sea for Turkey's energy independence will continue unabated."
At the same time, a naval warning was issued over Turkey’s intention to carry out operations south of a chain of islands lying between Crete and Cyprus, between August 10 and 23, Greek media reported.
Athens has said its military in the area has been put on alert and Greek Prime Minister Kyriakos Mitsotakis called a meeting of the country’s national security council.
On Thursday, Greece and Egypt announced a new agreement on exclusive economic zones in the eastern Mediterranean.
It was signed as a response to a maritime deal struck between Turkey and the Libyan Government of National Accord in Tripoli.
After the signing of the Greek-Egyptian deal, which has received the full backing of the UAE, Turkey restarted its exploration mission.
At the end of July, naval clashes between Greece and Turkey, both members of Nato, were only narrowly avoided after an 11th-hour intervention by German Chancellor Angela Merkel.
On Monday, Greek Minister of State George Gerapetritis said Athens was closely monitoring Ankara’s reaction.
"When we decided for the first time to exercise decisive diplomacy on issues related to the delimitation of the exclusive economic zones with Italy and, above all, with Egypt, we measured what the reaction would be,” Mr Gerapetritis told Greek television.
"It is obvious that this would bother them, given that this action practically neutralised the only basis of Turkish diplomacy, which was the non-existent and illegal Turkish-Libyan memorandum.
“The majority of the fleet is ready at the moment to go wherever required."
Greece and Turkey have been at odds for decades over access to areas of the eastern Mediterranean. Increasingly, the standoff has intersected with nine years of instability in Libya.
In December, the Turkish-backed GNA in Libya confirmed a new maritime border deal with Ankara in the Mediterranean Sea, in exchange for military co-operation.
The UAE, Egypt, France, Cyprus and Greece condemned the agreements, which would give Turkey access to potentially lucrative natural gas reserves in the area.
Differences in policy in the eastern Mediterranean have thrown into sharp relief contradictions in Nato and in the EU.
On Monday, Mr Mitsotakis spoke with European Council President Charles Michel to discuss Greece’s deal with Egypt.
He is scheduled to speak with Nato Secretary General Jens Stoltenberg on Monday evening.
