Russia’s Sloviansk Breakthrough Claim Is Not Independently Confirmed

Russia is applying sustained pressure across Donetsk, particularly around Pokrovsk, Kostiantynivka and the approaches to Sloviansk. But the available evidence does not establish the decisive breakthrough claimed by Russia’s chief of staff, Valery Gerasimov. The more cautious assessment is of incremental advances, infiltration attempts and heavy fighting alongside Ukrainian resistance and counterattacks. 456

What Gerasimov claimed about Sloviansk

On August 27, Gerasimov said Russian forces had broken through the first defensive line of the Sloviansk–Kramatorsk fortified area and were advancing across a front roughly 160 kilometres wide. He also said Russian troops were about four kilometres from Sloviansk’s eastern outskirts. Those statements were reported by Russian state-linked and Russian Ministry of Defence sources, making them claims by one side in the war rather than independently verified battlefield facts. 12314

Independent assessments support the existence of Russian movement east and southeast of Sloviansk, but not the full scale of Gerasimov’s description. ISW reported Russian advances east of the city while describing them as efforts to secure positions for possible future attacks on Sloviansk and the wider Fortress Belt. Earlier assessments also recorded Ukrainian advances or maintained Ukrainian positions in the Sloviansk direction. 456

The distinction matters: being able to infiltrate or reach isolated positions is not the same as controlling a continuous front or breaking through a fortified defensive system. ISW’s August 28 assessment also reported continued Russian operations without advances in some key sectors and limited Ukrainian tactical gains around Kostiantynivka.

Kostiantynivka and Pokrovsk remain the immediate pressure points

Ukraine’s General Staff reported 250 combat engagements on August 28, with 40 Russian attacks on the Pokrovsk front and 35 around Kostiantynivka—the heaviest concentrations reported that day. Seven Russian assaults were reported in the Sloviansk direction.

That pattern suggests that Russia’s operational effort is broader than a direct rush toward Sloviansk. Moscow is attempting to weaken Ukraine’s Donetsk defensive system from several directions, while pressure around Kostiantynivka threatens the southern part of the Fortress Belt. ISW has described Russian infiltration missions in and around Kostiantynivka, but earlier assessments found that these efforts had not produced an operationally significant seizure of the city.

Sloviansk’s status nonetheless reflects the growing danger. The Donetsk regional administration designated the city an active combat zone after heavy bombardment of Sloviansk and Kramatorsk, while Ukrainian authorities moved to reinforce the area’s defences. 7

Casualty and territory claims need careful treatment

Ukrainian President Volodymyr Zelenskyy said Russia had suffered 267,000 personnel losses since the start of 2026, including about 155,000 killed, and that 70–80% of Russian casualties were occurring near Kostiantynivka. These are Ukrainian official estimates and are not independently confirmed by the available evidence.

The broader picture does indicate severe Russian losses. ISW cited Ukrainian reporting of more than 42,000 Russian casualties in July, while also noting that casualty figures provided by parties to the war should be treated cautiously. Exact totals—and the distinction between killed, wounded and other losses—remain difficult to verify in real time.

Likewise, claims about Russia’s net territorial gains in August should not be presented as settled without a clearly identified methodology. ISW’s August 22 assessment recorded 8.52 square kilometres seized or infiltrated by Russian forces while saying Russia had lost 27.09 square kilometres of control during the month at that point. Those figures are not the same as a confirmed net Russian gain of 27 square kilometres.

Ukraine is trying to raise the cost of Russia’s offensive

Ukraine continues to target Russian military infrastructure, fuel production and logistics. Reported strikes have hit a major oil refinery and an airfield associated with Russian strategic aviation, while ISW assessed that Ukrainian attacks on oil infrastructure were continuing. 5

These strikes are intended to disrupt the systems that sustain Russia’s offensive—fuel, logistics, aviation and defence production. They may increase the cost of Russian operations, but they do not replace the need for Ukraine to hold the defensive belt around Kostiantynivka, Sloviansk and Kramatorsk.

A separate strategic development is the decision by Britain and France to help Ukraine obtain technology for domestic production of Storm Shadow/SCALP cruise missiles. Britain agreed to release classified technology, and France supported licensing for the French counterpart. 18 The measure could give Kyiv a more sustainable long-range strike capability, although it does not by itself prove that Ukraine has begun producing the missiles or that a specific Russian ballistic-missile facility will be targeted.

Europe’s financial debate is reopening

Spain, Sweden, Poland and the Netherlands are urging the European Union to resume work on using immobilised Russian sovereign assets to support Ukraine. Reuters reported that roughly €210 billion in Russian central-bank assets are frozen in the EU, while Belgium has continued to oppose the plan amid legal and financial concerns. 1719

The proposal remains politically and legally unsettled. For Ukraine, however, the debate is strategically important: predictable financing affects ammunition procurement, air defence, defence-industrial production and the state’s ability to sustain a long war.

Bottom line

Russia has the initiative in several Donetsk sectors and is exerting serious pressure on Ukraine’s defensive system. Yet Gerasimov’s claim that Russian forces are only four kilometres from Sloviansk and have breached the first defensive line is not independently established by the available battlefield assessments. 15

The best-supported conclusion is narrower: Russia has made local advances and is positioning forces for attacks on the Fortress Belt, while Ukraine continues to contest the approaches, reinforce Sloviansk and resist the pressure around Kostiantynivka and Pokrovsk. The next phase will depend less on a single headline claim than on whether Russia can convert infiltration and tactical gains into sustained control—and whether Ukraine can maintain its defences while expanding long-range strikes and securing European support.