U.S. President Donald Trump and Russian President Vladimir Putin indicated they would not attend what could be the first direct peace talks between Moscow and Kyiv in three years on Thursday, with the Kremlin sending instead a group of experienced technocrats.

Putin on Sunday proposed direct negotiations with Ukraine in Istanbul on Thursday "without any preconditions". Late on Wednesday, the Kremlin said the delegation would include presidential adviser Vladimir Medinsky and Deputy Defence Minister Alexander Fomin - but Putin's name was not on the list.

After the Kremlin's delegation announcement, a U.S. official said Trump, who is on a three-nation tour of the Middle East, would not attend. The U.S. leader had said earlier that he was considering the option to participate.

While Putin had never confirmed he would attend in person, the absence of the Russian and U.S. presidents lowers the expectations for a major breakthrough in the war that Russia started in February 2022.

Ukrainian President Volodymyr Zelenskiy had challenged Putin to attend the talks "if he's not afraid," in an apparent contest to show Trump who wants peace more, Ukraine or Russia.

While the Kyiv leader was on his way to Turkey late on Wednesday, a Ukrainian official said, he had said he would take part in the talks only if Putin attended.

In his nightly video address on Wednesday Zelenskiy said that Ukraine would decide on its steps for peace talks in Turkey once there was clarity on Putin's participation.

"The answers to all questions about this war – why it started, why it continues – all these answers are in Moscow," Zelenskiy said. "How the war will end depends on the world."

Trump wants the two sides to sign up to a 30-day ceasefire to pause Europe's biggest land war since World War Two, and a Russian lawmaker said on Wednesday there could also be discussions about a huge prisoner of war exchange.

Zelenskiy backs an immediate 30-day ceasefire, but Putin has said he first wants to start talks at which the details of such a ceasefire could be discussed.

MORE SANCTIONS ON RUSSIA?

Trump, who is growing increasingly frustrated with both Russia and Ukraine as he tries to push them towards a peace settlement, said he was "always considering" secondary sanctions against Moscow if he thought it was blocking the process.

U.S. officials have spoken about possible financial sanctions as well as potential secondary sanctions on buyers of Russian oil.

The U.S. delegation to Turkey included Secretary of State Marco Rubio and senior envoys Steve Witkoff and Keith Kellogg.

Ukrainian Foreign Minister Andrii Sybiha said early on Thursday he had met with Rubio to share Zelenskiy's peace vision and "coordinate positions during this critical week."

Medinsky and Fomin, part of the Russian delegation, took part in the last set of negotiations between the two sides in the first weeks of the war. Other senior military and intelligence officials were also part of the Thursday delegation.

Direct talks between negotiators from Ukraine and Russia last took place in Istanbul in March 2022, a month after Putin sent tens of thousands of troops into Ukraine in what he calls a "special military operation" to root out neo-Nazis.

Ukraine and its allies say the invasion was an unprovoked, imperial-style land grab.

With Russian forces grinding forward in Ukraine and now controlling about a fifth of the country, the Kremlin chief has offered few, if any, concessions so far. In his proposal at the weekend, he said that the talks in Turkey would be aimed at a durable peace.

He specifically mentioned the 2022 talks and the failed draft deal.

Under that deal, among others, Ukraine would have agreed to permanent neutrality in return for security guarantees from the five permanent members of the U.N. Security Council: Britain, China, France, Russia and the United States, and other nations including Belarus, Canada, Germany, Israel, Poland and Turkey, according to a draft seen by Reuters.

But officials in Kyiv say agreeing to Ukrainian neutrality is a red line they will not cross.