Ukrainian presidential aide Mykhaylo Podolyak on Monday called the International Olympic Committee a "promoter of war" after the sports body said it was considering ways for Russian athletes to compete at the 2024 Paris Olympics.
The IOC said last week it was examining a "pathway" for Russians to take part in the summer Games next year, probably as neutral athletes rather than under their national flag.
Russia and its ally Belarus have been sidelined from most Olympic sports since Russian forces invaded Ukraine last February.
"(The) IOC is a promoter of war, murder and destruction. The IOC watches with pleasure Russia destroying Ukraine and then offers Russia a platform to promote genocide and encourages their further killings," Podolyak said on Twitter.
"Obviously Russian money that buys Olympic hypocrisy doesn't have a smell of Ukrainian blood. Right, Mr. Bach?" he added, referring to IOC president Thomas Bach.
Ukraine's President Volodymyr Zelensky said Sunday Russia's participation in the Paris Olympics would amount to showing that "terror can allegedly be something acceptable".
"As if it is possible to turn a blind eye to what Russia is doing to Kherson, to Kharkiv, to Bakhmut and Avdiivka," Zelensky said in his nightly address, referring to cities under constant Russian attacks.
Zelensky added that he had sent a letter to President Emmanuel Macron on the matter following a phone call with the French leader last week.
"We must be sure that Russia will not be able to use it (the Olympics) or any other international sporting event to promote aggression or its state chauvinism," he said.
Ukraine's Sports Minister Vadym Goutzeit has warned his country could boycott next year's Olympics if Russian and Belarusian athletes are allowed to take part.
Ukraine's foreign minister Dmytro Kuleba said on Monday that of the 71 medals that Russian competitors won at the 2020 Tokyo Olympics, 45 were won by athletes who were members of the Central Sports Club of the Russian Army, or CSKA.
"The army that commits atrocities, kills, rapes, and loots," Kuleba said. "This is whom the ignorant IOC wants to put under (the) white flag allowing (them) to compete."
The Olympic Council of Asia last week offered Russian and Belarusian athletes the chance to compete in this year's Asian Games.
That was a significant move because it allows athletes from those two countries to gain qualifying standards they need to compete at the Paris Olympics.
Paris Mayor Anne Hidalgo has said she would be in favour of Russians taking part in Paris as neutrals but the Paris organisers have no say over which nations compete in Olympic Games.
The IOC reiterated last week that the international federations for each Olympic sport were "the sole authority for its international competitions."