(Reuters) -U.S. Senator Lindsey Graham disputed Russian criticism of his support for Ukraine on Sunday, saying he had simply praised the spirit of Ukrainians in resisting a Russian invasion with assistance provided by Washington.

Graham, shown in a video clip of his meeting with Ukrainian President Volodymyr Zelenskiy in Kyiv on Friday, acknowledged his host's praise for military assistance valued at $38 billion since the outset of the conflict in February 2022.

He described the help as "the best money we've ever spent".

Kremlin spokesman Dmitry Peskov denounced Graham, suggesting his comment on U.S. financial assistance was linked to a later remark that Russians "are dying" in the conflict.

But the release by the Ukrainian president's office of Graham's complete remarks showed there was no such link.

Graham said he was visiting on the 457th day of a war that Russia had assumed would be completed within three days and Graham said Ukrainians resisting the invasion reminded him of "our better selves in America. There was a time in America that we were this way, fighting to the last person, we were going to be free or die."

"Now you are free," Zelenskiy responded in the encounter. "And we will be."

Graham replied: "And the Russians are dying."

Zelenskiy then added: "Yes, but they came to our territory. We are not fighting on their territory."

Peskov and other Russian officials directly linked Graham's praise for the benefits of U.S. assistance to his comments on Russians dying in the conflict.

Initial extracts of the conversation released by Zelenskiy's office had not made clear that the two remarks were made in different parts of the conversation.

Peskov castigated the senator in comments to the Shot Telegram channel, saying: "It is difficult to imagine a greater shame for a country than having such senators."

Russian Security Council Deputy Chairman Dmitry Medvedev called Graham, a 67-year-old Republican, an old fool.

"The old fool Senator Lindsey Graham said that the United States has never spent money so successfully as on the murder of Russians," Medvedev said. "He shouldn't have done that."

Graham shot back at the criticism.

"As usual the Russia propaganda machine is hard at work," Graham told Reuters in an emailed statement on Sunday, referring to Medvedev's comments about his Kyiv visit, which he had used to urge Washington to send more weapons to Ukraine.

Graham said he had mentioned to Zelenskiy "that Ukraine has adopted the American mantra, 'Live Free or Die.' It has been a good investment by the United States to help liberate Ukraine from Russian war criminals."

He added, "Mr. Medvedev, if you want Russians to stop dying in Ukraine, withdraw. Stop the invasion. Stop the war crimes. The truth is that you and (President Vladimir) Putin could care less about Russian soldiers," he said.

Ukrainian presidential adviser Mykhailo Podolyak said in Twitter comments on Sunday that the best investment the United States and the West could make was "in a complete and unconditional victory of Ukraine".

(Reporting by Joey Roulette in Washington and Guy Faulconbridge in Moscow; Additional reporting by Max Hunder in Kyiv; Editing by Frances Kerry, Ron Popeski and Howard Goller)