It is still unclear whether Zelenskyj will have any role in the summit, which has primarily been planned for the leaders of the US and Russia, Donald Trump and Vladimir Putin, respectively.
But Zelenskyj warns against giving Putin anything.
"Russia refuses to stop the killing, and should therefore not receive any reward or benefits", he writes on social media. "This is not just a moral stance – it is the rational one".
"Concessions do not help against a murderer", Zelenskyj adds.
The government in Kyiv fears that Trump wants to make a deal over the head of Ukraine, and then promise Russia Ukrainian areas in exchange for an end to the fighting.
