Russian and Ukrainian delegations are set to meet at Istanbul's Ciragan Palace at 1 p.m. local time (10 a.m. GMT) Monday to discuss a potential cease-fire, according to a Turkish Foreign Ministry source.

Ukrainian President Volodymyr Zelenskyy said earlier Sunday that Defense Minister Rustem Umerov will be leading his country's delegation.

"I outlined (Ukraine's) positions ahead of the meeting in Istanbul on Monday," Zelenskyy wrote on Telegram on Sunday after meeting with his officials.

Zelenskyy listed Ukraine's positions for the talks as a complete and unconditional ceasefire, the release of prisoners, the return of abducted children.

"And, in order to establish a reliable and lasting peace and guarantee security, to prepare a meeting at the highest level."

Earlier, Russian Foreign Minister Sergey Lavrov stated that they had offered Ukraine to hold a new round of talks in Istanbul on June 2 and that Vladimir Medinsky, presidential aide to Vladimir Putin, would head the delegation.