Russian forces have gained ground on the eastern approaches to Sloviansk and continue to prioritize an eastern route toward the city, according to the Institute for the Study of War (ISW). Their earlier push from the northeast had bogged down, and Russia now aims to set up a future assault on one of the last major cities Ukraine still holds in Donetsk Oblast. A quick move on the city itself remains extremely unlikely, ISW said.

Russia's 2026 summer campaign in the east has advanced through field edges and small villages rather than the breakthroughs the Kremlin keeps promising, the grinding pattern that has defined the fighting across Donetsk Oblast for years.

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The eastern approach

Ukrainian military observer Kostiantyn Mashovets reported that Russian forward units are advancing across several tactical areas at once in the Sloviansk direction. He said the command of Russia's 3rd Combined Arms Army rushes assault infantry forward right after each successful infiltration. Russian troops reached the southeastern edge of Pyskunivka, east of Sloviansk, from the east and northeast, moving off positions they had seized on the southern bank of the Siverskyi Donets, Mashovets said. Zakitne lies northeast of Pyskunivka and Kryva Luka southeast of it, and ISW read the advance as evidence Russia has consolidated positions in both.

They also infiltrated the southern and southeastern outskirts of Mykolaivka from western Rai-Oleksandrivka. ISW assessed that Russia is running a dual effort to connect its units near Kryva Luka with those at Rai-Oleksandrivka, so it can assault Mykolaivka from dominant terrain to the east and south at once. Mashovets added that other Russian groups slipped through three settlements along the E-40 Bakhmut-Sloviansk highway, trying to hold the western bank of the Siverskyi Donets-Donbas Canal and reach the river just east of the city.

ISW observed reports on 23 August that Ukrainian forces repelled a Russian infiltration attempt in Mykolaivka.

Oleksandr Borodin, spokesperson for Ukraine's 3rd Army Corps, said the Lyman direction falls in his corps' zone and that Russia's goal there is to half-encircle the Sloviansk-Kramatorsk agglomeration from the flank—first securing bridgeheads across the rivers, then cutting logistics. He called those plans unrealistic:

"We have quite serious defensive positions there and have been preparing for a long time. The capabilities they currently have to try to accomplish this task are insufficient even to come close to achieving such a goal."

Why Moscow switched directions

Russia prioritized attacking Sloviansk from the northeast through Lyman when it opened its spring-summer 2026 offensive, but that effort has largely stalled. The Siverskyi Donets River, which loops north and northeast of the city, together with a web of canals, handed Ukrainian defenders a natural moat. So Russian commanders now treat Mykolaivka as a key prize. Taking it would let them strike west toward Sloviansk from the east, skirting the water obstacles that blocked the northeastern route.

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A slow road into the Fortress Belt

Sloviansk anchors the northern end of Ukraine's Fortress Belt, a chain of fortified cities that has blunted Russian advances in Donetsk Oblast since 2014. ISW cautioned that Russian forces are extremely unlikely to make fast gains west of Mykolaivka, since they still need to seize several more settlements first.

Ukraine's President Volodymyr Zelenskyy said on 23 August that Putin has ordered his army to seize all of Donetsk Oblast by 31 December. By ISW's count, it is the 15th such deadline since 2022, and Russia has missed every one that has come due.

Zelenskyy put Russia's frontline casualties this year at around 267,000, including about 155,000 killed, and said 70% to 80% of them fall in the Kostiantynivka direction. Russia holds about 79.89% of Donetsk Oblast, by ISW's count, and Zelenskyy said the Kremlin is preparing to mobilize around 300,000 men after the 18–20 September State Duma elections, partly to reinforce Donetsk and Luhansk oblasts.

Ukrainian analysts warn that the situation on a key stretch of the Donetsk front is becoming increasingly dangerous for two cities central to Ukraine's defense. The eastern flank of the Sloviansk-Kramatorsk agglomeration is taking on an increasingly threatening character, and earlier stabilization measures are clearly not working, military analyst Oleksandr Kovalenko said.

The two cities anchor the line that has held Russia back for over a decade. Sloviansk and Kramatorsk form part of the so-called fortress belt, the line of Ukrainian fortifications that has restrained the Russian advance since 2014. The agglomeration serves as the most important bastion and logistics hub for Ukrainian forces in the east. A threat to it is a threat to the backbone of Ukraine's defense in Donbas.

Russia is 12 to 13 km away

Kovalenko laid out how close Russian forces have come. Their forward positions are 12-13 kilometers from Sloviansk and Kramatorsk. He warned that if Russia's pace does not slow, the first infiltrations into both cities could come by December 2026.

The advance is measured in ground lost. The problem on the eastern flank runs about 30 kilometers, where Russia's 3rd Combined Arms Army operates.

"Only in the third week of August, Russian forces captured 21 square kilometers of Ukrainian territory in this section of the frontline," the expert said.

Russia uses the terrain of the "Cretaceous Flora" reserve, its hilly micro-relief rather than open steppe, to advance, absorbing not just square kilometers into pockets but villages and settlements.

The flank threatens neighboring sectors

The deterioration is spreading pressure sideways. The advance creates pressure from the southern bank of the Siverskyi Donets on the zone of the 3rd Army Corps, which had stabilized the Lyman direction and pinned Russian forces near Yampil, Kovalenko believes. The former Siverskyi direction saw the fastest rate of territorial loss of any sector in 2025, slowed in April and May 2026, but the 3rd Combined Arms Army's advance has not yet been stopped.

The cumulative loss is large. After losing more than 500 square kilometers over a year, the unstable flank, sagging since June 2025, is becoming a problem for other directions, looming over or pressuring them.

Kovalenko argued the sector has gone months without attention while threatening both the main agglomeration and the successfully held directions around it.

Analysts urge reinforcement before it is too late

Kovalenko proposed a specific fix. The sector must be reinforced as soon as possible, he said, suggesting that the nearest resource, Andrii Biletsky's 3rd Army Corps, often described as one of the most capable formations in Ukraine's forces, be used at least to relieve both banks of the Siverskyi Donets.

"Once infiltrations into Sloviansk and Kramatorsk begin, reinforcing garrisons and landing intelligence-directorate troops will not solve the problem but only delay the inevitable," he warned.

A second analyst gave a similar warning. Yurii Butusov, a drone company commander in the National Guard's "Khartia" corps, said that if Ukraine's forces retreat from there, Russia gains tactical advantages and Sloviansk-Kramatorsk is gradually lost, ultimately leading to the loss of the Donbas.

He also said that only Biletskyi can take responsibility for this battle.

"Only orderly command and organization at the front now will allow us to turn the course of a battle that is so far not going in our favor," Butusov said.