Washington's top diplomat discussed the Israel-Hamas war with Turkey's mercurial leader on Saturday before flying to Crete to address Greek concerns about the looming sale of US fighter jets to Ankara.
US Secretary of State Antony Blinken's high-stakes meeting with one of Washington's most unruly NATO allies came on the first leg of a trip that includes visits to Israel and West Bank.
Blinken's fourth crisis tour of the three-month-old Gaza war comes with fears mounting that the conflict could engulf swathes of the Middle East.
The State Department said Blinken "emphasised the need to prevent the conflict from spreading" during more than an hour of talks with President Recep Tayyip Erdogan.
Blinken stressed the need to "work toward broader, lasting regional peace that ensures Israel's security and advances the establishment of a Palestinian state," the State Department said.
A Turkish diplomatic source said Foreign Minister Hakan Fiden pressed Blinken during a separate meeting for an "immediate ceasefire" that could ensure the smooth delivery of aid.
Istanbul served as a base for Hamas political leaders until raids on Israel killed around 1,140 people and triggered a reprisal offensive that the Gaza health ministry says has claimed more than 22,700 lives -- most of them women and children.
Turkey asked the Hamas chiefs to leave after some were captured on video celebrating the deadliest attack in Israel's history.
- Strident critic -
Erdogan has since turned into one of the Muslim world's harshest critics of Washington's support for Israel's destructive Gaza campaign.
Erdogan has compared Israeli Prime Minister Benjamin Netanyahu to Adolf Hitler and accused the United States of sponsoring the "genocide" of Palestinians.
He has also rebuffed US pressure to cut off the suspected flow of funding through Turkey to Hamas and defended the group as legitimately elected "liberators" fighting for their land.
The US State Department on Friday announced $10 million in rewards for information about five alleged Hamas foreign operatives -- three of them believed to be based in Turkey -- thought to be helping finance the Iran-backed group.
Erdogan began to tone down his most strident comments after US President Joe Biden last month called the Turkish leader for the first time since the war broke out.
The call helped push along NATO member Turkey's glacial progress in accepting Sweden into the US-led defence organisation in the wake of Russia's war on Ukraine.
A key parliamentary committee approved Sweden's application in late December.
Some analysts believe Biden's call also secured Blinken's meeting with Erdogan. The Turkish leader notably left the city during Blinken's last visit two months ago.
- Assurances -
Blinken entered the talks hoping to win assurances that a ratification vote on Sweden's accession to NATO will be held soon by Turkey's full parliament.
The State Department said Blinken and Erdogan discussed "completing Sweden's accession to NATO and strengthening trade and investment between the United States and Turkey".
Erdogan has been able to use Turkey's veto power to impel Sweden into taking a tougher stance with Kurdish groups in Stockholm that Ankara views as "terrorists".
He has also been trying to make Sweden's approval conditional on the US delivering 40 US F-16 fighter jets and nearly 80 modernisation kits for Turkey's ageing air force.
Biden's administration officially backs the sale.
But Biden has been unable to overcome resistance in Congress from lawmakers who express alarm about Turkey's position on Sweden and past military standoffs with historic rival Greece.
US administration officials expect the sale to win congressional backing soon after Turkey ratifies Sweden's candidacy.
Blinken flew from Istanbul to the Greek island of Crete for talks with Prime Minister Kyriakos Mitsotakis.
Athens has fiercely resisted the US jet sales because of longstanding territorial disputes with Turkey in the energy-rich eastern Mediterranean region.
Greece is seeking to purchase a batch of more advanced F-35 jets from the United States to counter the perceived Turkish threat.