US President-elect Donald Trump called on Sunday for an immediate ceasefire and negotiations between Ukraine and Russia to end “the madness”, prompting Ukrainian President Volodymr Zelenskiy and the Kremlin to list their conditions.

Trump made his comments just hours after meeting Zelenskiy in Paris for their first face-to-face talks since Trump won last month’s US election. Trump has vowed to bring about a negotiated end to the conflict, but so far has not provided details.

“Zelensky and Ukraine would like to make a deal and stop the madness,” Trump wrote on his social media platform Truth Social, adding that Kyiv had lost some 400,000 soldiers. “There should be an immediate ceasefire and negotiations should begin.”

“I know Vladimir well. This is his time to act. China can help. The World is waiting!” Trump added, referring to Russian President Putin.

Trump, in Paris for the reopening of Notre-Dame Cathedral, sat down with Zelenskiy on Saturday for about an hour, along with host President Emmanuel Macron.

Trump and Zelenskiy shook hands and smiled, but it was unclear how the conversation had gone. Accounts of the talks from the French and Ukrainian sides said only that the discussions had been good and productive.

Zelenskiy reacted to Trump’s message on Sunday saying peace was not just a piece of paper, but needed guarantees.

“When we talk about effective peace with Russia, we must first and foremost talk about effective guarantees for peace. Ukrainians want peace more than anyone else,” he said on X.

“It (the war) cannot simply end with a piece of paper and a few signatures. A ceasefire without guarantees can be reignited at any moment, as Putin has already done before. To ensure that Ukrainians no longer suffer losses, we must guarantee the reliability of peace and not turn a blind eye to occupation.”

It appeared Trump’s figure of 400,000 Ukrainian soldiers lost in the war meant both killed and wounded. Zelenskiy said 43,000 soldiers had been killed in the war and that there had been 370,000 wounded soldiers.

Kremlin spokesman Dmitry Peskov convened a conference call with reporters to address Trump’s comments.

Peskov said Russia was open to talks, but that they had to be based on agreements reached in Istanbul in 2022 and on current realities on the battlefield where Russian forces have been pushing forward at their fastest rate since the early days of the war in 2022.

Putin has said repeatedly that a preliminary agreement reached between Russian and Ukrainian negotiators in the first weeks of the war at talks in Istanbul, which was never implemented, could serve as the basis for future talks.

“Our position on Ukraine is well known,” said Peskov.

“The conditions for an immediate stop to hostilities were set out by President Putin in his speech to the Russian Foreign Ministry in June of this year. It is important to recall that it was Ukraine that refused and continues to refuse negotiations,” he said.

Putin has said that Ukraine must not join the NATO military alliance and that Russia should be left fully in control of four Ukrainian regions his troops partially control at the moment for a peace deal to be done.

Peskov noted that Zelenskiy had banned contacts with the Russian leadership through a special decree, which Peskov said would have to be revoked if talks were to proceed.