Around 20,000 Russian troops were killed during Russia's failed offensive in Kharkiv Oblast, President Volodymyr Zelensky said in an interview with the BBC on July 18.
Russia launched its offensive on Kharkiv Oblast in May, pressing towards Ukraine's second-largest city, but the assault quickly stalled.
"We stopped this offensive, and their attack failed. This is a fact," Zelensky said.
"About 20,000 of their people died. These villages cost them."
The Kyiv Independent was unable to independently confirm the figure.
In June, Ukraine's Khortytsia group of forces said Russian forces suffered around 4,000 losses during their offensive in northern Kharkiv Oblast. The number includes troops killed or injured.
Mediazona, a Russian independent media outlet, and BBC Russia have confirmed the identities of 59,168 Russian soldiers who have been killed as of July 12 since the outbreak of the full-scale invasion.
The research was conducted using open sources, including obituaries published in the media and social networks and photos of graves and military monuments. The true toll may be significantly higher.
In the BBC interview, Zelensky declined to provide an updated count of how many Ukrainian troops have been killed in the war, citing security concerns. In February, he said that 31,000 troops had been killed.