US secretary of state Antony Blinken has said Turkey is committed to playing “a positive, productive” role for post-war Gaza and is prepared to use its influence in the region to prevent the Israel-Hamas conflict from broadening.

The latest Middle East mission by America’s top diplomat opened with talks in Turkey and Greece before shifting to the region for “not necessarily easy conversations” with allies and partners about what they are willing to do “to build durable peace and security”.

Mr Blinken’s fourth visit in three months comes as developments in Lebanon, northern Israel, the Red Sea and Iraq have put intense strains on a US push to prevent a regional conflagration since Hamas attacked Israel on October 7, and as international criticism of Israel’s military operation mounts.

He held meetings with Turkey’s President, Recep Tayyip Erdogan, and foreign minister, Hakan Fidan, in Istanbul about what Turkey and others can do to exert influence, particularly on Iran and its proxies, to ease tensions, speed humanitarian aid deliveries to Gaza and begin planning for reconstruction and governance of post-war Gaza.

Much of the territory has been reduced to rubble by Israeli bombardments.

In Chania, a port city on the Mediterranean island of Crete, Mr Blinken later visited Greece’s Prime Minister, Kyriakos Mitsotakis, at his residence. “These are difficult and challenging times,” Mr Mitsotakis said.

Mr Blinken’s day ended in Jordan, with stops in Qatar, the United Arab Emirates and Saudi Arabia to follow on Sunday and Monday.

He will visit Israel and the West Bank on Tuesday and Wednesday before wrapping up the trip in Egypt.

Mr Blinken said his priorities are protecting civilians – “far too many Palestinians have been killed” – getting more humanitarian aid into Gaza, ensuring Hamas cannot strike again and developing a framework for Palestinian-led governance in the territory and “a Palestinian state with security assurances or Israel”.

The ultimate goal, he said, is lasting peace, and his talks will focuses on what US allies and partners are prepared to do to help with that process.

He said: “These are not necessarily easy conversations. There are different perspectives, different needs, different requirements, but it is vital that we engage in this diplomacy now both for the sake of Gaza itself and more broadly the sake of the future for Israelis and Palestinians and for the region as a whole.

“There is clearly a strong desire among the majority of people in the region for a future that is one of peace, of security, of de-escalation of conflicts, of integration of countries and that’s one path, that’s one future.

“The other future is an endless cycle of violence, a repetition of the horrific events that we’ve seen and lives of insecurity and conflict for people in the region, which is what virtually no-one wants.”

Turkey, and Mr Erdogan in particular, have been harshly critical of Israel and Israeli Prime Minister Benjamin Netanyahu for the prosecution of the war and the impact it has had on Palestinian civilians.

But Mr Blinken told reporters before he flew from Crete to Amman that “from our conversations today, it’s clear that Turkey is prepared to play a positive, productive role in the work that needs to happen the day after the conflict ends and as well more broadly in trying to find a path to sustainable peace and security”.

Mr Blinken would not go in details about what he heard from the Turkish officials.

“I think they’re also prepared … to use the ties, the influence they have, the relationships they have with some of the critical players and some of the critical countries in the region to do everything possible to deescalate and to prevent the conflict from spreading,” he said.

“They clearly have a shared interest with us in doing just that and I’m confident from these conversations that they’re going to make every possible effort.”

From the Turkish officials, Mr Blinken sought at least consideration of potential monetary or in-kind contributions to reconstruction efforts in Gaza and participation in security arrangements, according to US officials.

Mr Blinken also stressed the importance that the US places on Turkey’s ratification of Sweden’s membership in Nato, a long-delayed process that the Turks have said they will complete soon.

Sweden’s entry to the alliance is seen as a significant response to Russia’s invasion of Ukraine.

A Turkish official said Mr Fidan told Mr Blinken that Israel’s “increasing aggression” in Gaza was a threat to the region and he called for an immediate cease-fire and the delivery of “uninterrupted” humanitarian aid.

Mr Fidan said negotiations for a two-state solution should begin “as soon as possible,” according to the official.

He also said Turkey was awaiting the outcome of its request to upgrade its fleet of F-16 fighter jets and stressed that the ratification of Sweden’s Nato membership lay in the hands of the Turkish parliament.