In a comment for Suspilne news outlet, Ukraine's military intelligence spokesperson Andrii Yusov responded to reports on the alleged use of Western-made weapons by Russian anti-Kremlin militia fighting on Ukraine's side.
Yusov said such questions should be addressed to the Russian Volunteer Corps and the Freedom of Russia Legion as they "operate autonomously" on Russian territory.
"As for other issues, I think the Ministry of Defense will comment appropriately," added Yusov.
On June 3, the Washington Post wrote that Russian anti-government militants had purportedly used riffles made by Belgium and the Czech Republic as well as tactical vehicles initially sent to Ukraine by U.S. and Poland in their May 22 cross-border raid on Russia's Belgorod region.
Belgian Prime Minister Alexander De Croo said that his country would launch an investigation into the purported use of its weapons on Russian soil.
The New York Times also reported the anti-Kremlin militias having used American-made armored vehicles during their operations in Russia.
The article claimed that the groups appear to have used International MaxxPros models of Mine-Resistant Ambush Protected vehicles (MRAPs), known to be provided to Ukraine only by Washington.
On May 24, White House spokesman John Kirby said the U.S. was looking into those reports.
The Free Russia Legion and the Russian Volunteer Corps claimed responsibility for fighting within Russia and taking hold of Russian villages near the Ukrainian border.
Ukraine's officials have issued mixed statements in response to the May 22 Belgorod region incursion.
Yusov confirmed told Suspilne that while the operation aimed to create a "safe strip" at the Russo-Ukrainian border, it is conducted "exclusively by Russian citizens." He then told CNN that the units that had crossed the border were "part of defense and security forces" in Ukraine, but "in Russia, they are acting as independent entities."
Mykhailo Podoliak, an advisor to the head of Ukraine's Presidential Office, denied any involvement by Kyiv.