President Volodymyr Zelenskyy has said that Russia was giving Ukraine an ultimatum at peace negotiations, but said he was ready to hold direct talks with Russia's Vladimir Putin and US President Donald Trump "any day".
His comments on Wednesday came after Russian and Ukrainian delegations in Istanbul swapped terms for agreeing to a ceasefire and said they were ready to host another round of prisoner exchanges.
Zelenskyy told reporters that the Russian document outlining Moscow's requirements to halt its invasion amounted to an ultimatum.
"That is, it is not a memorandum of understanding. At least a memorandum of understanding should be signed by two parties, not just one party demanding something," he said, sitting around a table with international and Ukrainian media.
"Therefore, it cannot be called a memorandum. It is, after all, an ultimatum from the Russian side to us," he added.
Ready for summit
He said that he was ready to hold a meeting with Putin and Trump.
"We are ready for such a meeting any day," Zelenskyy said, referring to a summit proposed by Turkish President Recep Tayyip Erdogan adding that he was proposing that a ceasefire be put in place before any such summit.
The White House said that Trump was "open" to meeting his Russian and Ukrainian counterparts in Türkiye after the two sides failed on Monday to make headway towards an elusive ceasefire.
Zelenskyy added that Ukraine and Russia were prepared to exchange captured military personnel this weekend, following the agreement between Moscow and Kiev brokered in Türkiye this week.
"The Russian side has passed on information that this weekend - on Saturday and Sunday - they will be able to transfer 500 people, 500 of our military," Zelenskyy said.
"We will be ready to exchange the relevant number" of prisoners of war, he added.
Tens of thousands have been killed since Russia launched its military campaign in Ukraine, with swathes of eastern and southern Ukraine destroyed and millions forced to flee their homes in Europe's largest refugee crisis since World War II.
