Frontline report: Russia tried to break through Sumy — now Ukraine threatens its troops from behind

Today, there is important news from the Sumy direction.

Ukraine advances into Kursk

Here, Ukrainian forces are advancing into the Kursk region, turning what was once a defensive stand into a renewed cross-border push. These gains now open the path to outflank and encircle Russian positions from the north to crush the already overstretched enemy lines and reshape the dynamics of the entire front.

A key factor behind this success has been the relentless Ukrainian air strike campaign against Russian reinforcements and command centers across both Sumy and Kursk. This has created openings for Ukrainian ground units to press forward. The Ukrainian Black Swan battalion recently released footage northeast of Kindrativka showing Russian aircraft attempting to bomb new Ukrainian positions, a sign of how far north the battle has shifted.

Despite Russian air activity, Ukrainian advances in this area underscore the collapse of Russia’s ability to maintain pressure in Sumy, with Ukrainian forces now fighting beyond the settlements that were once planned to serve as a foothold for Russia’s push south.

Drone warfare reshapes the battle

Complementing air strikes, Ukraine’s drone campaign is inflicting devastating damage on Russian positions at the tactical level. Heavy drone platforms like the Vampire hexacopter are proving decisive, flying long-range night missions with payloads up to 20 kilograms. These drones are not just dropping improvised explosives but carrying devastating ordnance, including anti-tank mines and a series of mortar rounds, which complicate Russian attempts to maneuver. Most notably, Ukrainian engineers working with frontline units have introduced a new drone-dropped munition dubbed the black hole bomb. Developed by the Ukrainian Black Swan unit, the weapon has two confirmed variants. The thermobaric version unleashes a high-temperature blast wave that sucks in surrounding air, annihilating fortifications and suffocating troops caught inside trenches or buildings. The fragmentation variant detonates overhead, scattering lethal shrapnel across wide areas, ideal for clearing entrenched infantry or enemy units on the move. Combat footage shows these black hole munitions creating huge craters and collapsing Russian firing points, their effect comparable to that of artillery shells but instead delivered with surgical precision from the sky. This innovation allows Ukrainian units to dismantle Russian defenses without waiting for conventional artillery or risking exposure of expensive fighter jets to Russian air defense systems.

Russia’s defense collapses

With Russian forces concentrated in Sumy and stretched thin after weeks of costly attacks and devastating air strikes, Ukrainian commanders have again opted for tactical maneuvers rather than frontal attrition. Instead of smashing head-on into Russia’s lines, they are methodically cutting off isolated groups, collapsing salients piece by piece, and pushing back into Kursk in the process. This strategy takes advantage of the area, where settlements are small, scattered, and dispersed, making it easier to bypass and encircle Russian detachments rather than fight through each one in sequence.

Ukrainian advances north of Kindrativka and into rural Kursk show this logic in action, turning the international border into little more than a reference line. In practice, the fighting forms a unified battle space where Ukraine’s forces cross back and forth, exploiting Russian vulnerabilities while ignoring state boundaries that no longer reflect realities on the ground. The result is a steadily deteriorating situation for the Russian command, and what began as an attempt to push into Sumy has now backfired, with Ukraine not only halting the incursion but clawing back ground across the frontier. Russian infantry, deprived of supplies and hammered by Ukrainian air and drone strikes, cannot establish a coherent defense, and by advancing north, Ukraine is opening the possibility of flanking Russian troops still holding pockets of territory in Sumy from behind, threatening their lines of retreat and accelerating their collapse.

Overall, Ukraine’s steady progress highlights how momentum has shifted from a desperate defensive fight to prevent Russian forces from reaching Sumy city into an operation pushing enemy troops back into Kursk.

The border itself is losing meaning in the chaos of battle, and Ukraine is now able to carry the fight onto Russian soil to disrupt the enemy’s remaining footholds. With innovation in drone warfare, effective use of air power, and smart maneuvering, Ukrainian forces are not just defending but are reshaping the frontline to their advantage. In our regular frontline report, we pair up with the military blogger Reporting from Ukraine to keep you informed about what is happening on the battlefield in the Russo-Ukrainian war.