The Turkish navy had said last month that the Yavuz would stay in eastern Mediterranean waters southwest of Cyprus until October 12.

But the Vessel Finder tracking site said the ship began pulling out of the disputed region on Sunday and entered the Turkish port of Tasucu early Monday.

Turkey issued no official comment.

The apparent de-escalation came as Erdogan prepared to hold talks in Ankara later Monday with NATO chief Jens Stoltenberg about its dispute with Greece and Cyprus about maritime borders and energy rights.

NATO members Greece and Turkey have rattled the military alliance by staging rival war games in August to support their territorial and energy claims.

The conflict began to ease when they agreed last month to resume direct negotiations in Istanbul for the first time since 2016. No date for the talks has been announced.

Last month, Turkey pulled its Oruc Reis energy research vessel back to shore after more than a month-long mission near a Greek island that it supported with naval warships.

Erdogan had said at the time that if Turkey withdrew the vessel, "it means let's give diplomacy a chance."

EU leaders warned on Friday they could sanction Turkey if it failed to stop its unilateral actions and continued drilling activities.

Ankara rejected the threat as "unconstructive".

NATO last week helped the neighbours set up a military hotline to head off accidental clashes.

Announcing the "de-confliction mechanism" on Thursday, Stoltenberg said it would "create the space for diplomatic efforts to address the underlying dispute and we stand ready to develop it further."

Stoltenberg will visit Athens on Tuesday for talks with Greek Prime Minister Kyriakos Mitsotakis.