Russian sabotage units tried unsuccessfully to cross the Ukrainian border into Sumy and Chernihiv oblasts, Lieutenant General Serhii Naiev said on July 21.
"The Russian Federation does not cease trying to find weak points in our defense in the Chernihiv and Sumy directions," the general wrote on Telegram.
"A penetration of sabotage groups at the border was recorded, but all attempts were unsuccessful."
Naiev said that the military is working together with local administrations to strengthen the security of the border regions by installing barriers and cameras.
In the case of an increased threat, the military will provide sufficient reinforcements to prevent the Russian forces from crossing into Ukraine's territory in these areas, the general added.
The Sumy and Chernihiv oblasts lie at Ukraine's northern border with Russia. Both of them were invaded and partially occupied during Russia's initial onslaught in February 2022, but the invading forces withdrew in April after the Kremlin's failure to take Kyiv.
Since then, settlements near the border in the two regions come under regular Russian strikes by missiles, drones, and artillery. Ukraine's military previously reported several repelled raids by Russian sabotage groups in Sumy Oblast.