The Ukrainian military intelligence (HUR) said on May 27 that it gained "valuable information" from the Belgorod Oblast incursion, which was carried out by Russian anti-government militia fighting alongside Ukraine in Russia's full-scale war.
The Ukrainian Defense Ministry's Intelligence Directorate representative Andriy Yusov did not elaborate further on the "valuable information."
Speaking on television, Yusov stressed not to undermine the Kremlin's reaction to the military operation carried out by Russian volunteer fighters.
On May 22, Russian militia groups – who call themselves the Russian Volunteer Corps (RVC) and the Free Russia Legion – broke into the bordering areas of Russia's Belgorod Oblast – bordering Ukraine's Kharkiv and Sumy oblasts.
Denis Kapustin, also known by his alias White Rex and ties to the Russian far-right, leads the so-called Volunteer Corps, told journalists on May 24 that his fighters were in Russian territory for about 24 hours and held "around 42 square kilometers" of land in Russia for "quite a while."
A fighter from the Free Russia Legion, who was authorized to speak to journalists and identified himself with call sign Tsezar (Caesar), said the operation's task was "to carry out deep reconnaissance in combat."
While the units claimed responsibility for the incursion, Russia immediately accused the Ukrainian military's "sabotage group" of launching a cross-border assault – a claim immediately denied by Kyiv.