The deal marks 'an audacious first step towards European strategic autonomy', Macron said.
France and Greece signed on Tuesday a multibillion-euro deal for Athens to buy three French warships, an accord hailed by President Emmanuel Macron as a major boost for the EU's defence ambitions.
The memorandum of understanding for the purchase of the Belharra frigates was inked less than two weeks after Paris was left reeling by Australia's cancellation of a contract to buy French submarines, in favour of a new defence pact with Britain and the US.
Macron said after meeting Greek Prime Minister Kyriakos Mitsotakis at the Elysee Palace that Greece would buy the three frigates from France to cement a deeper "strategic partnership" between the two countries to defend their shared interests in the Mediterranean.
The deal marks "an audacious first step towards European strategic autonomy," Macron said.
"Europeans must stop being naive" regarding geopolitical competition, Macron added, in particular as Washington increasingly takes a go-it-alone approach with regards to its EU allies.
"We're being asked to take more responsibility for our own protection; I believe this is a legitimate request, therefore it's up to us to do so," he said.
He called Athens' decision to buy the Belharra ships "a sign of confidence" in France's defence industry, against competition notably from the American group Lockheed Martin, according to press reports.
The deal also sent a clear signal from Paris after its stinging loss this month of a multibillion-euro contract for submarines with Australia, which announced it would instead buy nuclear-powered subs from the US.
The French leader has long insisted that Europe needs to develop its own defence capabilities and no longer be so reliant on the United States, even warning that Nato was undergoing "brain death".
"Today is a historic day for Greece and France. We have decided to upgrade our bilateral defensive cooperation," Mitsotakis said.
He said the agreement involves "mutual support" and "joint action at all levels," as well as an option to purchase a fourth frigate.
"Our two countries have developed a very powerful alliance that goes beyond our mutual obligations" as Nato allies, he said.
The ships are set to be delivered starting in 2024, in a deal to be finalised by the end of this year for a value of some $3.5 billion, a French defence ministry source told AFP.
The accord did not include the sale of any French Gowind corvettes, a possibility that had been mentioned in Greek media reports.
Mitsotakis added that the French deal would not affect talks on extending a longstanding defence cooperation agreement between Greece and Washington, despite the transatlantic tensions following the Australia submarines row.
The agreement is "not antagonistic" to the Greek-US relationship, he said, citing how "France stood by us during difficult times in the summer of 2020", a reference to Turkey's challenging of Greek territorial rights in the Aegean Sea.
Macron added that the frigate sale was not meant to be seen as a threat against Ankara, but a means to jointly ensure security in the Mediterranean as well as in North Africa, the Middle East and the Balkans.
Greece and France had already roused Ankara's ire in January, when they signed a $3 billion deal for 18 Rafale jets -- 12 used and six new -- as part of a burgeoning arms program to counter Turkish ambitions.
Earlier this month, Mitsotakis surprised many observers with plans to buy an additional six Rafale jets, bringing the total order to 24.
"It's not directed against anyone," Macron said. "It allows more efficient and coordinated action for peace, cooperation and stability, in an international order founded on the rule of law and the full respect of commitments."
A Turkish defence ministry official told AFP that Ankara was "taking note" of the frigate contract, without further comment.
Macron also vowed that the US-Australia pact would not impact France's strategy for the Indo-Pacific region, where China has made no secret of its desire to exercise significant military sway.