US special envoy Steve Witkoff is set to join talks with Ukraine's Volodymyr Zelensky and Turkish President Recep Tayyip Erdogan in Ankara on Wednesday, as the Ukrainian president said he wanted to "intensify" peace negotiations.

"Bringing the end of the war closer with all our might is Ukraine's top priority," Zelensky said, adding that efforts would also focus on resuming prisoner exchanges.

Turkey has maintained ties with both Kyiv and Moscow and has previously hosted talks between the two factions.

But no Russian representative is set to join the meeting in Ankara, Kremlin spokesman Dmitry Peskov said.

He added that while there were "no concrete plans" for Vladimir Putin to speak to either the Turkish side or to Witkoff, the Russian president was "of course open to a conversation".