Heraldo de Madrid - Russia, Ukraine begin talks in Istanbul

A source in the Ukrainian delegation said the heads of the two delegations held a preparatory meeting with Turkish Foreign Minister Hakan Fidan ahead of wider talks.

A source close to the Russian delegation said officials from the two sides had a bilateral meeting.

The two sides previously met in the Turkish city 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.

"No one expects an easy road. It will be very difficult," Kremlin spokesman Dmitry Peskov told reporters when asked about his expectations for the talks.

Ukraine said it hoped the two countries would discuss the release of prisoners and lay the ground for a meeting between President Volodymyr Zelensky and Russian counterpart Vladimir Putin.

"Everything will depend on whether Russia stops speaking in ultimatums and takes a constructive position," a source in the Ukrainian delegation told AFP.

"This will determine whether results can be achieved at this meeting."

But Moscow has said a lot of work is needed before even discussions can take place about possible talks between Putin and Zelensky, who last met in 2019.

- Crimea sticking point -

The two sides have radically different positions for 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 Kyiv 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 invasion, 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.

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. Ukraine has labelled him a puppet.

At the last talks on May 16 and June 2, 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".

- Russia claims advances -

Wednesday's talks come as the White House steps 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 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.

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, said the Ukrainian air force.

The Russian defence ministry said Wednesday it had captured the village of Varachyne in Ukraine's northern Sumy region, where Moscow has been advancing for weeks.

A Russian drone attack on the Sumy region cut power to more than 220,000 people earlier Wednesday, Zelensky said.

Turkey's President Recep Tayyip Erdogan last month called on both sides not to "shut the door" on dialogue.

H.Roldan--HdM