Russian President Vladimir Putin himself floated Istanbul as a venue for talks Thursday with Ukraine -- the city where Turkey hosted one round of talks between Moscow and Kyiv at the start of the war, with another round in Antalya.

It was in the coastal city of Antalya that NATO foreign ministers began gathering Wednesday evening on the eve of a meeting at which they will discuss ramping up defence spending.

And a new round of talks between Iran and the so-called E3 powers -- Britain, France and Germany -- is also likely to be held in Istanbul later this week.

Earlier Wednesday, Turkish President Recep Tayip Erdogan took part remotely in a landmark Riyadh meeting between Trump and Syria's new leader Ahmed al-Sharaa, praising the US leader's decision to lift sanctions on Damascus.

"Today, Turkey has become one of the centres of peace diplomacy," Erdogan boasted in a speech to lawmakers from his ruling AKP.

"One of the countries whose support, assistance and mediation is sought for resolving regional and global crises is, without a doubt, Turkey."

- US-backed Turkish diplomacy -

Analysts say Washington has gravitated towards Turkey thanks to the personal connection between Trump and Erdogan.

"Trump seems to love Erdogan, he seems to have truly warm personal feelings about him," Max Abrahms, an international security professor, told AFP.

"Turkey is a very important country in the world and there are thus many reasons why strong relations with Turkey help the US geopolitically," he said.

But the personal connection between them was "unmistakable, and frequently acknowledged by Trump", he said.

During their telephone conversation last week, Trump said he wanted to work with Erdogan to end Russia's invasion of Ukraine.

"I look forward to working with President Erdogan on getting the ridiculous, but deadly, war between Russia and Ukraine ended -- NOW!" Trump posted on his Truth Social network.

Erdogan stepped up diplomatic contacts at the weekend.

He spoke by phone with Putin and French President Emmanuel Macron, who visited Kyiv with the leaders of Germany, Britain and Poland Saturday in a show of solidarity with Ukrainian President Volodymyr Zelensky.

Together they urged Moscow to accept a 30-day unconditional ceasefire starting, with Zelensky saying he expected Putin to show up for Thursday's Istanbul talks.

-'Trump likes Erdogan'-

With little sign of Putin coming, it remains unclear who Moscow will send in his stead.

Trump said on Wednesday he would go if Putin also went.

Aaron Stein, head of the US-based Foreign Policy Research Institute, agreed that Ankara was now "the beneficiary of Donald Trump".

"He is the one that has forced discussions about a ceasefire that align with Ankara, therefore creating a need for a Turkish or Saudi venue for Ukraine talks," he told AFP.

On Iran, it's more or less the same vibe, he said.

Trump, he said, was "trying to undo his own policy error" of walking away from a landmark 2015 agreement between major powers and Iran that gave it sanctions relief in return for UN-monitored restrictions on its nuclear activities.

"Trump is very clear: he likes Erdogan."

A Turkish official, who requested anonymity, confirmed warm ties between the two leaders. But he added: "It's Trump who sets the degree of this warmth.

"The latest statements made by Trump carried the relationship to a more sincere level," the official told AFP. "Both leaders are looking to matters from a win-win perspective."

- 'Increasing room for manoeuvre' -

For Nigar Goksel of the International Crisis Group, Turkey's geography and its positioning itself over years of careful balancing gave it an upper hand.

"Ankara's advancing defence sector also increased its manoeuver space," she said.

NATO member Turkey has maintained good relations with both Ukraine and Russia. It has supplied Kyiv with drones while shying away from Western-led sanctions on Moscow.

"Success in these roles also reinforces Turkey's international stature and is popular domestically, serving the political interests of the government," Goksel told AFP.

Ukraine's Foreign Minister Andriy Sybiga, who met his Turkish counterpart, Hakan Fidan in Antalya, praised Turkey's role.

"The epicentre of world diplomacy is now in Turkey, which is playing an active mediation role. We appreciate it," he said.