The envoys travelled to Kyiv by train after flying to Poland – Zelensky told the media that it was not possible for them to land their plane despite preparations.

Putin and Zelensky agreed to halt strikes on each other's capitals for three days while the negotiators carry out their trip.

While Witkoff and Kushner were in talks at the Kremlin on Saturday, Zelensky said he and his team were "ready for a substantive conversation".

On Sunday, Zelensky wrote on social media that his country "has always been and will remain constructive".

"We are interested in bringing the end of the war closer. Peace is needed. Security guarantees are needed.

"A dignified character of the postwar peace is needed. Our proposals are ready," he said.

Overnight, Russian and Ukrainian forces continued to exchange strikes, with Ukraine confirming they struck an oil refinery, an airfield, and two air defence systems.

The country's defence ministry said they targeted the Ryazan oil refinery, which supplies the Russian army, and an airfield in Rostov-on-Don.

Earlier, Ukraine's Air Force reported that Russia attacked Ukraine with 108 long-range drones and small cruise missiles.

The country's air defences downed 82 drones and six missiles, but 11 locations were hit, with debris falling at a further seven sites.

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