From Kupiansk to Dnepropetrovsk, Russia exploits thin defenses as Ukraine struggles to plug the gaps As August gave way to September, the rhythm of the war shifted. The main fronts around Pokrovsk and Konstantinovka fell eerily quiet, while new fires broke out on the edges – Kupiansk in the north, Liman in the forests, and the flatlands of Zaporozhye and Dnepropetrovsk.The reason was clear enough: Ukraine’s commanders had stripped secondary sectors to feed counterattacks where the pressure was greatest. Around Konstantinovka the offensive ground to a halt, and on the Pokrovsk front Kiev’s forces even clawed back a little ground. But that gamble came at a price. With the line stretched too thin, cracks began to open. On three fronts at once, crises flared – warning signs that Ukraine can no longer hold the line everywhere at once. Russia, regrouping and readying fresh offensives, now has the chance to exploit those gaps and turn them into breakthroughs.What follows is a tour down the front from north to south – where the quiet lulls, the sudden shocks, and the looming sense of collapse set the stage for what may come next.Kupiansk: An unexpected assaultFor months, the Kupiansk sector looked like a dead end. Last year, Russian forces crossed the Oskol River, setting the stage for an assault on the city from the northwest. Then, in July 2025, they captured Kondrashovka and Moskovka – key strongholds in the area.For a while, Ukraine treated the Kupiansk defense zone the way it did the Serebrianskiye forests farther south: as a reserve pool to pull reinforcements from. But now Kiev’s resources here are starting to run thin. © RT / RT / Sergey Poletaev based on data from Lostarmor.Ru By mid-August, fighting had spilled into Kupiansk itself. By September 10, Russian troops had taken the central square, the main administrative building, several high-rises, and a sugar factory on the city’s eastern edge.The last viable supply route for Ukraine’s garrison – through the village of Blagodatovka – was cut off as the front line crept closer. A dirt road running south through Osinovo along the railway is also effectively unusable, under constant drone strikes.So what’s the situation now? A month earlier in Pokrovsk, a new pattern had emerged in the battle for a major city: neither side held steady ground, with most of the fighting carried out remotely using FPV drones. Kupiansk seems to be following the same script.Reports suggest Russian troops are also making heavy use of pipelines for covert infiltration behind Ukrainian lines. On September 19–20, intense clashes broke out in Yubileyny – the last remaining high-rise district not yet under Russian control.Liman and the Serebrianskiye Forests: From quantity to qualityThe offensive toward Liman has continued to gather momentum. One of September’s most significant developments was the capture of the Serebrianskiye forests, where battles had dragged on for more than two years, dating back to the fall of 2023. This victory opens the way to the settlement of Yampol and gives Russian forces fire control over a web of roads and crossings linking Liman with Seversk on the southern bank of the Seversky Donets River.To the west, fighting stretches from Shandrigolovo to Novoselovka. Over the past month, Russian troops have advanced as much as seven kilometers along a 10–11 kilometer front, seizing key strongholds and severing the road running northwest from Liman toward Izyum. © RT / RT / Sergey Poletaev based on data from Lostarmor.Ru What’s the picture now? The Ukrainian garrison in Liman has only one supply route left – through the damaged bridge over the Seversky Donets and on to Slaviansk. In May 2022, a similar bottleneck sparked fierce battles for the city that lasted less than a week before Ukrainian forces pulled out – though they later retook it in October of that year.This time, a lightning-fast assault seems less likely. Still, the longer the encirclement tightens, the more precarious the situation becomes for Ukraine’s troops inside Liman.Pokrovsk and the Northern front: Calm before the stormAfter Russia’s breakthrough north of Pokrovsk in August, Ukraine threw everything it had into counterattacks to keep the front from collapsing. By most Ukrainian accounts, nearly all available reserves were committed to these operations.On the other side, Russian forces focused on consolidating their new foothold and widening it. The strategy paid off to a degree: they took Vladimirovka to the east and Rubezhnoye to the west. But to avoid encirclement, Russian units had to pull back from the Dobropolye–Kramatorsk highway, which they had briefly controlled. © RT / RT / Sergey Poletaev based on data from Lostarmor.Ru In this sector, the map shifts almost daily. Even with extra reserves, Ukrainian forces have been unable to establish a continuous defensive line around the breach. For their part, Russian troops face difficulties massing forces in the narrow, exposed lowlands.So what’s happening now? In recent days, fighting has flared again around Pokrovsk and Mirnograd. If Moscow’s goal is to push farther north while threatening Kramatorsk from the flank, it will first need to deal with the sizable Ukrainian pocket around Pokrovsk and Mirnograd – straightening the front and freeing up manpower for the next phase.As in the summer, this stretch of the front is likely to see major developments in the weeks and months ahead.Dnepropetrovsk Region: Go WestThe most significant Russian gains this month have come along the Zaporozhye and Pokrovskoye axes. Here, Russian forces have pushed as far as 15 kilometers on a front roughly 40 kilometers wide. Daily reports note the capture of settlements not only in the Donetsk People’s Republic and Zaporozhye region, but also in Dnepropetrovsk.For Ukraine, the problem is structural: its defenses were built to face south, while the current offensive is coming from the east, along those very lines. Combined with the broader exhaustion of Ukraine’s forces, this leaves too little manpower to hold open terrain effectively. © RT / RT / Sergey Poletaev based on data from Lostarmor.Ru The only real Ukrainian progress in this area has been a series of counterattacks near Zeleny Gay, but these appear more an extension of the defensive fight around Pokrovsk and Dobropolye than independent operations.So where do things stand now? On September 20, Russia’s Ministry of Defense announced the capture of Berezovoe – the largest Ukrainian stronghold in the Dnepropetrovsk region so far. If Russian forces keep advancing, they could reach the Pokrovskoye–Gulaipole road on the border of Zaporozhye and Dnepropetrovsk and potentially encircle the city of Gulaipole.