The Ukrainian partisan group ATESH has claimed one of its agents successfully infiltrated a Russian air base and hinted at carrying out sabotage operations.
In a post on Telegram on June 22, the group said it had scouted the Baltimore airfield in Voronezh, around 220 kilometers north-east from the border with Kharkiv Oblast and home to Russia's 47th Guards Bomber Aviation Regiment.
Pictures and videos accompanying the post show several aircraft including a helicopter and what ATESH say are SU-34 fighter-bombers, a plane Russia frequently employs to launch missiles at Ukrainian cities.
"In some of them, Russians now have surprises waiting for them," the post reads.
ATESH also claimed to have passed on information about the base to Ukrainian authorities, adding: "Soon, we will see the result of our work."
The Kyiv Independent could not verify the photos or the claims made by ATESH.
The SU-34 is reported to have been the aircraft used in Russia's recent first use of the three ton FAB-3000 high-explosive aerial bomb in Kherson Oblast earlier this month.
A video claims to show a FAB-3000 bomb striking the end of a building used by the Ukrainian army as a temporary deployment point (TDP).
The post accompanying the video explains that the bomb did not succeed in making a direct hit on the target but still caused massive damage.
Ukraine could not confirm that Russia used the bomb, Air Force spokesperson Illia Yevlash said in a comment for the Kyiv Independent.
The ATESH movement is highly-active in both occupied areas of Ukraine and inside Russia itself.
On June 12, the group said a Russian satellite communication station was destroyed in a sabotage attack in Moscow Oblast.
In a video posted by Atesh partisans on Telegram, an Atesh agent is seen pouring a flammable liquid on an R-441 Liven communications satellite. The communications station is seen subsequently catching fire.
The incident allegedly occurred in the Klin district of Moscow Oblast - approximately 85 kilometers (over 50 miles) northwest of the Russian capital.