French and Greek naval vessels conducted joint exercises in the Eastern Mediterranean in response to continuing encroachment by Turkish warships and a seismic research vessel in the area.
A short video released by Greece’s military on Thursday showed Greek frigates conducting manoeuvres with a French vessel and helicopter.
The exercises we meant to raise the forces’ operational readiness and combat ability, the Greek TV channel Skai reported.
The show of support from France at sea follows Paris’s commitment of two Rafale fighter jets and a naval frigate to bolster dozens of Greek ships already on high alert in the Eastern Mediterranean.
Greek Prime Minister Kyriakos Mitsotakis thanked French President Emmanuel Macron as a “true friend of Greece” and a “fervent protector of European values and international law”.
The two spoke with Egyptian President Abdel Fattah El Sisi on Wednesday.
Mr Macron said after the call that he decided to "temporarily reinforce the French military presence in the Eastern Mediterranean in the coming days, in co-operation with European partners including Greece".
Diplomatic manoeuvrings continued before Friday's meeting between EU ministers to discuss the Eastern Mediterranean, and a summit between US Secretary of State Mike Pompeo and his Greek Foreign Minster Nikos Dendias, also on Friday.
The threat of sanctions hangs over Turkey after it sent a research vessel, the Oruc Reis, into contested Greek waters on Monday, escorted by six warships.
Greece called for the extraordinary meeting of EU foreign ministers to discuss sanctions.
Brussels has imposed such penalties on people linked to Ankara’s earlier drilling activities in the area.
Paris has also sought sanctions against Ankara in the weeks after a June incident in the Mediterranean between the two Nato allies’ naval vessels.
France claimed its frigate, the Courbet, was harassed by a Turkish vessel while watching a cargo ship suspected of taking weapons to Libya.
Paris ultimately withdrew the Courbet from Nato's mission in the Mediterranean over the disagreement.
Tension in the eastern Mediterranean have exposed the divisions between Nato members and have been a perennial headache for the alliance.
Nato Secretary General Jens Stoltenberg on Monday called for the stand-off to be resolved “in a spirit of allied solidarity and in accordance with international law”.
A spokesman for the bloc said there had been no change in its position since.
The dispute between Turkey and Greece stretches back decades and centres on areas bordering the many Greek islands in the region.
Turkey’s claims to the waters, which it says are on its continental shelf, have repeatedly been dismissed as illegal by Greece and its allies.
Renewed, competing claims by Greece and Turkey over the waters have crossed into the conflict in Libya.
In December Ankara and Libya’s Government of National Accord in Tripoli signed an agreement on maritime borders that favoured Turkey.
In exchange, Ankara promised military support to the government in Tripoli.
Last week Greece and Egypt agreed on their own maritime border deal.
The UAE has thrown its weight behind the Greek-Egyptian deal while Turkey has called the Cairo accord a provocation.
Ankara has indicated that it wants to return to the negotiating table over the competing claims to the resource-rich waters.
Turkey’s President, Recep Tayyip Erdogan, said on Thursday that the only solution to the dispute was through dialogue and negotiation.
Mr Erdogan said Ankara was not chasing any "adventures" in the region.
But at the same time, the Oruc Reis has continued to carry out surveys in the disputed waters, said the Turkish Energy and Natural Resources Minister, Fatih Donmez.
Mr Erdogan is to speak on Thursday with the German Chancellor Angela Merkel and EU Council President Charles Michel.