Kyiv said it orchestrated the assassination of a pro-Kremlin Ukrainian politician on Wednesday after an ex-lawmaker who had defected to Russia was shot dead outside Moscow.
Since Russia invaded last February, Ukraine has claimed to be behind a spate of assassinations and attacks on pro-war Russians and former Ukrainian officials who have backed Moscow's invasion.
A source in Ukraine's defence sector told AFP that its SBU security services had orchestrated the assassination of Illia Kyva, a former pro-Russian Ukrainian lawmaker who defected to Moscow when Russia invaded last year.
Russian investigators said Kyva had been shot.
His body was discovered in a park in the Moscow suburbs on Wednesday.
"An unknown person fired shots at the victim from an unidentified weapon. The man died on the spot from his injuries," Russia's Investigative Committee said in a statement.
It said it had opened a case into his death.
The Russian news agency TASS cited a police officer as saying the investigation was being treated as a "Ukrainian plot" and that search operations for the killer were underway.
Speaking on national TV, Ukraine's military intelligence spokesperson Andriy Yusov said: "We can confirm that Kyva is done. Such a fate will befall other traitors of Ukraine, as well as the henchmen of the Putin regime."
Yusov called Kyva "one of the biggest scumbags, traitors and collaborators" and said his death was "justice".
The day before Russia's invasion, Kyva said the country had been "soaked by Nazism" and needed "liberating" by Russia -- echoing talking points regularly advanced by Russian officials and on state TV.
He had written to Russian President Vladimir Putin requesting Russian citizenship, and a court in Ukraine had sentenced him in absentia to 14 years for high treason.
Kyva said in a Wednesday morning post on his Telegram channel that Ukrainian President Volodymyr Zelensky would "be better off killing himself".
Kyiv used to rarely comment on whether it was behind several killings of pro-Russian figures, both inside Russia and in parts of Ukraine occupied by Russian forces.
But lately, it has started to claim responsibility for a number of attacks and openly threatened to hunt down other "collaborators" and "traitors".
Moscow has previously said Ukraine was behind other audacious assassinations deep inside Russia's borders.
In August 2022, Russian nationalist Darya Dugina was killed outside Moscow in a car bombing, while an explosion at a Saint Petersburg cafe in April killed Russian military blogger Vladlen Tatarsky.
Ukraine has not publicly claimed responsibility for those attacks, though US intelligence and media reports have linked Kyiv to them.
Several lower-ranking Ukrainian officials and politicians who have welcomed Russia's invasion and worked for Russian-backed authorities in occupied parts of Ukraine have also been killed.
In a separate incident, a proxy lawmaker in Ukraine's eastern Lugansk region was killed in a car bombing attack also on Wednesday, Russian investigators said.
Oleg Popov, who served as a deputy in the pro-Moscow Lugansk regional parliament, was killed after the "detonation of an unidentified device in a car", Russia's Investigative Committee said, without providing details.
