Russia has warned that upcoming talks with Ukraine in Istanbul on Wednesday will be "difficult," tempering hopes for a breakthrough after more than three years of war.
Delegations from both countries have departed for Istanbul, with negotiations expected to begin later in the evening.
The two sides previously met in Istanbul in May and June, but managed to agree only on exchanges of prisoners and soldiers' bodies.
US President Donald Trump last week gave Russia "50 days" to end the war or face sanctions, but the Kremlin has not indicated it is willing to compromise on its demands.
"No one expects an easy road," Kremlin spokesperson Dmitry Peskov told reporters when asked about his expectations for the talks.
"It will be very difficult," he added.
Ukraine said it hoped the two sides would discuss the release of prisoners and lay the ground for a meeting between Ukrainian President Volodymyr Zelenskyy and Russian leader Vladimir Putin.
Moscow has said that "a lot of work" is needed before even discussions can take place about possible talks between Putin and Zelenskyy, who last met in 2019.
Radically different positions
The two sides have radically different positions on ending the conflict.
Russia has called on Ukraine to effectively retreat from the four Ukrainian regions Moscow claims to have annexed in September 2022, a demand Kiev has called unacceptable.
Ukraine has ruled out any negotiations on territory until after a ceasefire and says it will never recognise Russia's claims over occupied territory – including Crimea, which Moscow annexed in 2014.
Russia's full-scale offensive, launched in February 2022, has ravaged swathes of eastern and southern Ukraine, killing tens of thousands of soldiers and civilians.
Ukraine said former Defence Minister Rustem Umerov, who currently serves as Security Council secretary, would head its delegation.
Medinsky leads Russian delagation
The Kremlin said it would send political scientist Vladimir Medinsky to lead its negotiating team.
Medinsky, who led the Russian delegation in the two previous rounds of negotiation, is not seen as a powerful decision-maker and has been described by Ukraine as a puppet.
At the last talks on 16 May and 2 June, the two sides agreed to large-scale prisoner exchanges.
They also exchanged their draft terms for ending the conflict, which the Kremlin said were "diametrically opposed".
Trump’s deadline
Wednesday's talks come as the White House ramps up pressure on Russia to agree a compromise.
Trump announced last week he was giving Russia until September to strike a peace deal with Ukraine or face bruising sanctions.
The US leader has been trying to broker an end to the war since his inauguration in January, but has failed to extract any concessions from the Kremlin, despite repeated phone calls with Putin.
War continues
Russia has meanwhile intensified its bombardment of Ukrainian towns and cities, while advancing across several different areas of the front line.
Between late Tuesday and early Wednesday, Russia fired 71 drones at four different regions of Ukraine, according to the Ukrainian air force.
The Russian Defence Ministry said on Wednesday that it had captured the village of Varachyne in Ukraine's northern Sumy region.
Türkiye's President Recep Tayyip Erdogan last month called on both sides not to "shut the door" on dialogue.
