'Meaningful progress' made in Ukraine war talks: Witkoff

US envoy Steve Witkoff has said that talks between Ukraine and Russia had "brought about meaningful progress" in the Washington-led drive to end the war in Ukraine, as both sides were set to begin a second day of negotiations in Geneva.

"President Trump's success in bringing both sides of this war together has brought about meaningful progress, and we are proud to work under his leadership to stop the killing in this terrible conflict. Both parties agreed to update their respective leaders and continue working towards a deal," he wrote on X on Wednesday.

Ukrainian and Russian negotiators were to resume a second round of US-mediated peace talks in Geneva on Wednesday, though neither side signalled they were any closer to ending Europe's deadliest conflict since World War II.

The talks are the latest diplomatic bid to halt the fighting, which has killed hundreds of thousands, forced millions to flee and decimated much of eastern and southern Ukraine.

The United States has been pushing for an end to the nearly four-year war, but has failed to broker a compromise between Moscow and Kiev on the key issue of territory.

Two previous rounds of negotiation between the two sides in Abu Dhabi failed to yield a breakthrough.

‘What do they want?’

The latest talks "were very tense", a source close to the Russian delegation told AFP.

"They lasted six hours. They have now concluded," the source said, speaking on the condition of anonymity.

Ukrainian President Volodymyr Zelenskyy said in his evening address that he was ready "to move quickly towards a worthy agreement to end the war", but questioned whether Russia was serious about peace.

"What do they want?" he added, accusing them of prioritising missile strikes over "real diplomacy".

Russia launched its full-scale war in Ukraine in February 2022, with the ensuing conflict resulting in a tidal wave of destruction that has left entire cities in ruins.

For the Geneva talks, the Kremlin reinstated nationalist hawk and former culture minister Vladimir Medinsky as its lead negotiator.

Ukrainian national security secretary Rustem Umerov was leading Kiev's side and said negotiations would continue on Wednesday.

He thanked Washington for its mediation and said he informed European allies of the outcomes from the first round of talks, which he said had focused on "practical issues and the mechanics of possible solutions" to the conflict.