Ukrainian special forces said on Monday that they had destroyed an unmanned observation tower in Russia’s Bryansk region using a drone strike, a rare public acknowledgment of a cross-border attack that underscored Kyiv’s increasing willingness to directly strike Russian territory.
The Kraken unit, which reports to Ukrainian military intelligence, released a video that it said showed the assault on its Telegram channel on Monday.
The strike’s timing was unclear, but the video came days after a brief armed incursion into a Russian border village in Bryansk by a group claiming to fight for Ukraine, a rare known case of a raid inside Russia. The Kremlin described it as a “terrorist” attack.
The Russian Volunteer Corps, a group opposed to President Vladimir V. Putin of Russia, claimed on Thursday that it briefly took control of the small village of Lyubichane, near the border with northeastern Ukraine. There were conflicting reports about the episode and what took place in Bryansk, but by the end of the day, the Russian authorities said the group had been driven back into Ukraine.
Russia and Ukraine share a land border extending more than 1,200 miles, including several hundred miles in the eastern Donbas region, parts of which are controlled by Moscow. Russia has used territories close to Ukraine — including Bryansk, along Ukraine’s northern border — to stage assaults, fire rockets, launch air assaults and mount other attacks throughout the war.
Officials in Kyiv have said they reserve the right to strike targets within Russia that they claim are used to attack Ukrainian towns and cities, but have promised not to use weapons supplied by Western allies for such assaults, since allies fear Moscow could view that as a provocation.
Over the course of the yearlong war, explosions and fires have been reported at oil depots, rail hubs and other military targets in Russia, but Ukraine has maintained a policy of deliberate ambiguity over such attacks, very rarely claiming responsibility.
Ukraine is believed to have struck inside Russia on several occasions, including in December, when the Engels Air Base, which is about 300 miles from the Ukrainian border, was attacked twice.
On Monday, the governor of the Russian region of Belgorod, which also borders Ukraine, said that Russian air defenses had shot down three missiles in the city of Novy Oskol. The Ukrainian authorities did not comment on the Russian claims.
But the Ukrainian government has expressed growing concern that Moscow is using the Bryansk region to launch drone assaults. The latest such attack, it said, took place before dawn on Monday. Alarms blared across Kyiv as air-defense guns echoed. The Ukrainian Air Force said it had detected at least 15 drones launched from Bryansk and claimed to have shot down 13.
Kyiv’s forces also continued to target Russian strongholds in occupied areas of Ukraine. Two large explosions were reported Sunday night in the Russian-occupied city of Melitopol in southern Ukraine, the city’s exiled mayor, Ivan Fedorov, said in an appearance on national television. Mr. Federov said that the Ukrainian military was still working to confirm the damage from the strike.
The Russian military has also continued to fire long-range missiles and drones at Ukraine’s cities and energy grid. The death toll from a Russian missile strike on an apartment building in the city of Zaporizhzhia last week has since risen to 13, Ukrainian officials said Sunday.
