Two Days Without a Breakthrough: ISW Records the Failure of Russian Attacks on Key Frontline Sectors

For two consecutive days — September 20 and 21, 2026 — the Russian armed forces made active attempts to break through the Ukrainian defense on several axes, yet, according to a fresh report by the Institute for the Study of War (ISW), they managed to achieve virtually no confirmed successes anywhere. The fiercest fighting took place in the Sumy, Kharkiv, and Donetsk regions, where both sides intensified the tempo of combat operations. This is reported by RBC-Ukraine, citing an ISW analytical piece.

Sumy Axis: the Gas Pipeline as a "Bridge" for Raids

In the northern part of Sumy Oblast, Russian units resumed attempts to penetrate Ukrainian territory via the Urengoy–Pomary–Uzhhorod trunk gas pipeline from the Sudzha direction. According to Ukrainian military sources, over the past week the occupiers twice used the pipeline as a corridor for tactical raids, but they failed to advance beyond its limits. The Ukrainian defense on this sector held its integrity, and the breakthrough attempts were repelled.

Kharkiv and Lyman Axes: Counteroffensive and Repelled Attacks

In the Kharkiv region, Russian forces recently advanced in Volchansk, but Ukrainian forces responded with strikes on enemy positions in the southern part of the town, stabilizing the situation. Meanwhile, Moscow's claims of capturing the settlements of Pylina and Novoleksandrivka are assessed critically by ISW analysts: according to their data, Russian units are located at a considerable distance from the aforementioned villages and do not control them. Near Lyman, Ukrainian military forces continue counteroffensive operations against the enemy grouping. On September 20 and 21, the Russians launched attacks on this axis, but no confirmed advances were recorded.

Slaviansk and Konstantinivka Axes: Intensified Fire Preparation

On the Slaviansk axis, the occupiers attempted to attack near Krynivka and toward Mykolaivka, but to no avail. At the same time, as ISW notes, the Russians are systematically increasing the use of drones, artillery, and aviation, preparing the battlefield for subsequent breakthrough attempts. Near Konstantinivka, Russian forces continued offensive operations to the west and southwest of the town, accompanied by airstrikes on Ukrainian positions and infrastructure. Nevertheless, no confirmed advance on this sector was recorded on September 20 and 21.

Dobropillia Axis and Operation "Vivaldi"

On the Dobropillia axis, the occupiers are attempting to infiltrate in small groups, supporting their attacks with airstrikes. However, Ukrainian drones prevent the enemy from consolidating on captured positions. ISW emphasizes that, despite the high tempo of attacks on this axis, the Russians have achieved very few confirmed results there. A separate episode of the "Vivaldi" offensive operation in the north of Donbas deserves particular attention: the Third Army Corps of the Ukrainian Armed Forces, for the first time in the world, air-dropped a ground-based robotic suicide complex more than 10 kilometers behind enemy lines. The devices were delivered there by heavy bomber drones of the Third Assault Brigade, while Ukrainian units simultaneously employed electronic warfare means to conceal the offensive's intent.

Contradictory Data

The key discrepancy between the two sides' accounts concerns the Kharkiv axis. The Russian side claims to have captured the settlements of Pylina and Novoleksandrivka. However, ISW analysts, relying on open sources and geolocation, point out that Russian units are located at a considerable distance from these villages and do not in fact control their territory. Thus, until independent confirmation emerges (for example, verified video with geodata or satellite monitoring data), information about the full capture of these settlements remains disputed. The Ukrainian side, for its part, does not confirm the loss of control over the aforementioned settlements.

Strikes on Infrastructure: "Kasta" Radar and a UAV Command Post

Meanwhile, the Ukrainian Armed Forces, on the night of September 21, destroyed a rare "Kasta" radar station worth approximately 60 million dollars in the Pikuzy area of Donetsk Oblast, and also struck the occupiers' unmanned aerial vehicle command post near Dniproenerhiiya. These strikes significantly limit the Russian side's capabilities for detecting aerial targets and coordinating drone operations on this sector of the front.