The Failed Offensive: An analysis of the causes of the summer’s setbacks leads Putin to consider a new mobilisation

A failed offensive: net, gross and qualitative statistics

It is now reasonable to state that Russia’s summer offensive ‘on the ground’ in 2026 failed to materialise. According to calculations by the Ukrainian Armed Forces-linked OSINT project DeepState.UA, the increase in territory captured by Russian forces over the four months from May to August amounted to approximately 140 square kilometres; the corresponding figure for 2025 was 2,030 square kilometres. By this measure, the pace of the Russian army’s advance fell 15-fold. This result, however, represents the difference between the Russian forces’ gross territorial advance, at 390 square kilometres, and the gains made by Ukrainian counteroffensives, which the project estimates at 250 square kilometres. But even if we look at the ‘net advance’ of Russian troops, it is five times lower than last year’s rate, at 2,050 square kilometres over four months (Figure 1). The Black Bird Group’s calculations are very similar: an advance of 310 square kilometres in May–August 2026, compared with an advance of 1,890 square kilometres in the same months of 2025.

Figure 1. Rate of advance of the Russian and Ukrainian armies, 2024–2026, square kilometres

Over the eight-month period since the beginning of the year, Russian forces captured 810 square kilometres in 2026, compared with 2,860 square kilometres in 2025. The pace of net territorial gains fell from 2,890 square kilometres in 2025 to 1,140 square kilometres this year, a decline of 2.5-fold. According to calculations by Black Bird Group, Russian forces advanced 820 square kilometres this year, compared with 2,840 square kilometres last year, representing a 3.5-fold slowdown. As these figures and Figure 2 clearly show, the dynamics of the fighting changed radically from May compared with the previous year: the pace of advance during the summer months was even lower than during the first, winter months of the year.

Figure 2. Rate of advance of the Russian army in 2025 and 2026, square kilometres

In reality, the advance of Russian forces appears even more modest. Drone warfare and the infiltration tactic, which has become the main method of the Russian offensive, are expanding the grey zone of uncertainty along the line of contact. The Institute for the Study of War (ISW) has been tracking territorial changes while taking this factor into account since November 2025. According to these calculations, in August the area of firm Russian army control increased by 90 square kilometres, while the infiltration zone expanded by a further 33 square kilometres. In July, the increase in the area of firm control was even smaller, at around 40 square kilometres, while the infiltration zone expanded by approximately 85 square kilometres (see Figure 3; a negative increase on the graph indicates that the area under firm control contracted that month, whilst the infiltration zone may have expanded, and vice versa). Overall, according to this calculation method, since May, the Russian forces’ zone of secure control has shrunk by 120 square kilometres, whilst the grey zone has expanded by 440 square kilometres. Since the start of the year, accordingly, the zone of control has increased by 225 square kilometres, and the infiltration zone by 640 square kilometres.

Figure 3. Growth in the Russian army’s zone of secure control and zone of infiltration, square kilometres 

Although the accuracy of classifying territory as belonging to one zone or another may be the subject of endless debate, this methodology highlights an important feature of the current phase of the war: the blurring of the concept of the front line (or line of contact) and the expansion of the grey zone, which both sides may regard as ‘their own’ and within which positions are, in reality, intermingled.

The expansion of this zone creates the impression that the Russian offensive has not, after all, come to a complete halt. According to TASS’s calculations based on reports from the Russian Ministry of Defence, Russia took control of 91 settlements over the summer. At the same time, the Russian offensive gained momentum: 20 settlements were captured in June, 32 in July and 39 in August. However, the Ukrainian Telegram channel DeepState reported that only seven settlements fell under enemy control in August, including five in the Donetsk region (Rodynske, Shakhove, Sukhetske, Illinivka and Pryvillia) and two in the Kharkiv region (Riznykivka and Artelne).

The reason is that expansion of the infiltration zone rarely translates into genuine tactical success: Russian groups are unable to consolidate their positions in the territory they enter, says Volodymyr Hirniak, a spokesperson for the 53rd Separate Mechanised Brigade. He notes that the Russian army has for a considerable time been attempting to reach the approaches to Lyman, which is regarded as a ‘gateway for further operations’, but has been unable to resolve the problem of logistics and supplying its forward units. Similarly, military analyst Konstantin Mashovets writes that although the Russian army has made significant advances in Donbas, it has still not been able to deploy its frontline units to the immediate approaches to the Druzhkivka defence sector of the Ukrainian Armed Forces and launch an assault on it.

Casualty estimates and signs of a shortage of manpower

Overall, based on the territorial-advance statistics cited above, two key changes in the nature of the fighting can be identified. First, Russia has failed to develop its summer offensive after the winter pause. Second, Ukrainian counterattacks have become a systematic phenomenon this year. Since the beginning of the year, according to DeepState’s calculations, the Ukrainian Armed Forces have recaptured around 330 square kilometres. This is still roughly a quarter of the territory captured by Russian forces, but is substantially more than the 70 square kilometres regained through successful counterattacks in 2025 and the 20 square kilometres regained in 2024. Ukraine has effectively neutralised the threat of encirclement of Lyman and now, conversely, poses a threat to the Russian bridgehead to the north of the city, as the Black Bird Group concludes in its assessment of the situation in August. OSINT analyst Clément Molin writes that, during a four-month operation, the Ukrainian Armed Forces liberated more than 200 square kilometres, cutting off the salient formed by the Russian army to the north of Lyman. Meanwhile, the new Commander-in-Chief of the Ukrainian Armed Forces, Mykhailo Drapatyi, claims that, in total, the Ukrainian Armed Forces liberated 745 square kilometres in 2026. Such estimates, however, are not reflected in the calculations by DeepState and the Black Bird Group.

Meanwhile, according to the General Staff of the Ukrainian Armed Forces, Russian army losses exceeded 42,000 personnel in August and amounted to 158,000 over the four months of the failed offensive (May–August), or 39,500 per month. During the previous four months at the beginning of the year, losses amounted to approximately 122,000, while in May–August 2025, during a period of more active battlefield advances, they were just over 130,000. Thus, according to these figures, losses over the past four months were 30% higher than during the preceding months of the low-intensity phase of the offensive and 20% higher than during last year’s active offensive phase. This means that the failure of Russia’s summer offensive in 2026 does not necessarily indicate a decline in contract recruitment in Russia: the increase in the intensity of losses alone may have altered the balance of forces. Ukrainian military bloggers note that the slow pace of the Russian offensive, particularly in the Orikhiv direction, is linked to the need to redeploy forces from one sector to another in response to Ukrainian counterattacks. Attempts to concentrate troops on the main axis of attack, in turn, create opportunities for such counterattacks.

Thus, one of the factors behind the failure of the Russian summer offensive of 2026 was a shortage of manpower due to the increased level of casualties on the Russian side. As a result, the rising losses are proving ineffective: they are not translating into further territorial gains. Measured against the increase in captured territory (net gains, after deducting areas retaken by the Ukrainian Armed Forces), Russian losses during last year’s summer offensive phase (May–August) amounted to 64 personnel per square kilometre. During the lower-intensity winter advance (January–April), this had already risen to 182, while during the failed summer offensive it reached the staggering level of 832 personnel per square kilometre.

Figure 4. Russian army casualties according to the General Staff of the Ukrainian Armed Forces, 2025–2026

The role of mid-range strikes: no lockdown, but an effect

In our review this spring, we suggested that the Russian summer offensive might not materialise as a result of the strengthening of Ukraine’s unmanned defence capabilities and a campaign of mid-range strikes ( –> Re:Russia: The Zone of Absolute Death). We were proved right. The ISW drew attention to the role of medium-range strikes in complicating logistics in the near rear as a factor slowing Russia’s ground advance in late May and then again in early August. Ukrainian drone expert Dmytro Putiata claimed that depots and command posts, previously located 60–80 kilometres from the front line, were being moved to depths of over 100 kilometres and beyond. In May, Russian ‘military correspondents’ sounded the alarm on this matter (see Radio Free Europe’s review, in particular a post on the ‘Ghost of Novorossiya’ channel: ‘The front is moving significantly more slowly than the enemy is expanding and deepening the zone of active, controlled UAV strikes against our rear... Over the past month, the enemy has carried out very intensive and, once again, controlled strikes against a number of targets: maintenance units, warehouses, troop deployment areas, and so on.’). According to Clément Molin’s calculations, in the first few months of the year the Ukrainian Armed Forces struck only a few dozen lorries in Russian-occupied territories; in May, more than 200; and in the summer, around 600 per month. In mid-July, the commander of the Ukrainian National Guard, Oleksandr Pivnenko, explicitly stated that the use of operational-depth strike drones had enabled an increase in the rate at which Russian logistics, equipment and warehouses were being targeted, thereby constraining Russia’s ability to conduct its offensive.

The website of Ukraine’s ‘Unmanned Systems Forces Group’ (USF) keeps records of targets struck. Based on its data, Re: Russia’s calculations show that average monthly figures for Russian infrastructure targets struck across several categories (warehouses, vehicles and specialised equipment, tactical infrastructure, ground-based robotic systems, shelters and bunkers) rose sharply in the spring and early summer, but stabilised in July–August (the growth in the number of motor vehicles, tactical infrastructure and warehouses hit came to a halt). This may be due both to the relocation of facilities further into the rear and to the Russian side strengthening the defence of roads by increasing the number of mobile fire support units along the routes, as the ISW noted in mid-August. Despite significant progress, the objective of a ‘logistical lockdown’ set in May by then Minister of Defence, Mykhailo Fedorov, intended to completely paralyse the Russian army’s ability to conduct offensive operations, has not been achieved. Experts noted as early as mid-summer that this would require scaling up the use of unmanned aerial vehicles for mid-range strikes to a new level.

Figure 5. Index of damage to Russian rear infrastructure based on data from the ‘Unmanned Systems Forces Group’, October 2025 = 100%

The siege of the ‘belt’: will the autumn offensive take place?

Vladimir Putin has tasked the military with completing the occupation of Donbas by the end of the year. According to other reports, the deadline was extended to six months at the military’s request. In any case, since 2022 Putin has set deadlines for completing the Donetsk operation at least 15 times, as President Zelensky noted.

Whatever the exact deadline, the central element of such an operation would have to be the siege of the famous ‘fortress belt’. Our analysis of Ukrainian General Staff reports for August shows that the Pokrovsk and Kostyantynivka axes accounted for a combined 43% of all combat engagements during the month (1,702 out of 3,942). If we include all axes associated with the offensive against the ‘fortress belt’, including its core (Kostyantynivka, Slovyansk and Kramatorsk), its northern flank (Lyman) and its southern approaches (Pokrovsk), they account for almost two-thirds (63%) of all combat engagements in August.

Figure 6. Russian-Ukrainian combat engagements by axis, August 2026

The fighting for Kostyantynivka (the capture of which Putin claimed as early as the beginning of July) is currently of fundamental importance, writes Ukrainian military expert Dmitry Snegirev. It is an integral part of the Kostyantynivka–Druzhkivka–Kramatorsk–Slovyansk line and a major rail and road hub. Its capture would cut logistical links to Ukrainian units on adjacent sections of the front. Capturing Kostyantynivka would give Russian forces access to the immediate approaches to Kramatorsk from the south and east, which is their main operational objective, notes Konstantin Mashovets. Russia achieved ‘significant tactical results’ in this direction in August thanks to the advance of Russian assault groups on the flanks of the Ukrainian Armed Forces’ Kostyantynivka defensive area, successful advances by forward units in the Slovyansk direction, and the Russian army’s advance in the Dobropillia area. These developments prevented the Ukrainian command from concentrating sufficient forces to defend Kostyantynivka and Druzhkivka, Mashovets writes. However, even after 11 months of siege, the Russian army still does not control a significant part of the city: ISW estimates that, as of 1 September, Russian troops had occupied 70% of the urban area.

The autumn period itself may prove to be significantly more challenging for the Ukrainian defence, according to a number of analysts. The loss of Starlink access for Russian forces and the expansion of Ukraine’s drone capabilities, both quantitative and qualitative, including the mass deployment of Hornet drones, created a ‘window of opportunity’ for Ukraine in the spring. As Defence Minister Fedorov warned at the time, this window would close within four to six months as Russia adapted to the new realities and expanded its own drone capabilities. Some analysts believe that deteriorating weather conditions will reduce the effectiveness of drone operations (a similar effect was observed during the intensification of the Russian offensive last autumn); however, others argue that the falling leaves make infiltration more difficult.

As things stand, it can be stated that, according to DeepState.UA’s calculations, the Russian offensive accelerated in early September, reaching around 80 square kilometres in the first nine days of the month. During equivalent periods in May and June, Russian forces advanced by approximately 20 square kilometres, and in July by 35 square kilometres. A recent military briefing by Meduza notes a deterioration in the situation along the Dobropillia–Druzhkivka sector (the authors even describe it as a ‘full-blown crisis’ for the defence).

Ukrainian OSINT analyst m0nstas takes a pessimistic view of the autumn period: ‘In October, Russia’s advance already reached its peak, and the signs point to a repetition of this trend: a significantly larger stockpile of bombs and strike drones than a year ago,’ he argues. To advance in Donbas, the Russian army is using the method of battlefield air interdiction (BAI), which created the conditions for Russian advances near Pokrovsk and Huliaipole, as the ISW agrees. This tactic involves using aircraft to strike the near rear in order to isolate defensive units from their logistics. As part of this campaign, the Russian army has increased its strikes against railway locomotives and bridges. Overall, however, analysts see no preconditions under the current status quo for a major Russian breakthrough of the kind that President Putin appears to be counting on.

The appointment of Mykhailo Drapatyi as the new Commander-in-Chief of the Ukrainian Armed Forces has prompted cautious optimism among analysts. He is expected to give commanders of major formations greater autonomy, which should improve coordination in the defence. Michael Kofmann, Rob Lee and several others take this view. Drapatyi has reformed the command structure of the ‘fortress belt’: the sector from Lyman to Kramatorsk/Kostyantynivka will be led by Andriy Biletsky, commander of the 3rd Army Corps, whilst the second sector (Dobropillia) will be led by Denys Prokopenko, commander of the 1st ‘Azov’ Corps. The publication Hromadske, citing sources within the General Staff of the Armed Forces of Ukraine, reports that the decision should help units in Donbas adopt the command methods of Biletsky and Prokopenko, which are regarded in Ukraine as among the most effective.

At the same time, there is widespread scepticism about the prospect of resolving the Ukrainian front’s key problem: replenishing manpower. Although Zelensky has given Drapatyi a mandate to reform the mobilisation system, the task appears virtually insurmountable at this stage, according to Viktor Kevlyuk, an analyst at the Centre for Defence Strategies, and many other experts. In effect, this represents the central challenge for developments over the autumn and winter.

As can be seen from the analysis presented here, the failure of Russia’s summer offensive was linked to the fact that, against the backdrop of expanding Ukrainian drone-defence capabilities, Russian forces suffered heavier losses than in previous periods. As a result, they lacked sufficient manpower to concentrate forces on the main axes of attack while simultaneously protecting other sections of the front from Ukrainian counterattacks. From a purely military perspective, therefore, based on an analysis of the situation on the ground, a sharp increase in Russian manpower could be seen as a potential opportunity to create a decisive advantage.

Without this assumption, Putin’s setting of yet another deadline for the completion of the operation makes absolutely no sense. An analysis of the reasons for the failure of the summer offensive should, in our view, lead the Russian military leadership and President Putin to decide to carry out another round of ‘partial’ mobilisation. All the more so because, in the opinion of most analysts, Ukraine is currently, in all likelihood, politically incapable of carrying out mobilisation on its own.