Russian troops enter more of Kostiantynivka but fail to seize central rail hub

Russia’s Bakhmut and Dzerzhynsk (Toretsk) tactical groups advanced south of Kostiantynivka and into the eastern part of the city, ISW said.

Ukrainian military analyst Kostiantyn Mashovets said on June 10 that units of Russia’s Bakhmut tactical group advanced from Stupochky through Novodmytrivka northeast of Kostiantynivka, as well as along the T-0504 Pokrovsk-Bakhmut road toward the Kostiantynivka railway station. Mashovets said Russian forces had captured the southern part of Novodmytrivka.

Mashovets also said units of the Dzerzhynsk tactical group advanced from Illinivka into several districts of Kostiantynivka and near the railway station, and made a tactical breakthrough in the west-central part of the city.

Forward assault units from the two Russian tactical groups are about 2 kilometers, or 1.2 miles, apart. Russian forces, however, have failed to take control of the railway station in Kostiantynivka. Ukrainian forces also pushed Russian saboteurs out of the Dovha Balka area southwest of the city, Mashovets said.

ISW analysts said Russian forces began their offensive against Kostiantynivka in summer 2025 after advances around Chasiv Yar and the capture of Toretsk, then intensified their efforts in winter 2026.

Russian forces captured Toretsk in August 2025 after a 14-month campaign and have since advanced about 9 kilometers, or 5.6 miles, toward Kostiantynivka. By August 2025, after more than two years of fighting, Russian forces had managed to take control of most of Chasiv Yar. Ukrainian forces counterattacked in March 2026 and renewed the battle for the city. Despite the prolonged fighting, Russian forces still have not fully pushed Ukrainian defenders out of Chasiv Yar.

Russian forces first entered Kostiantynivka in October 2025 and have since maintained a presence in at least 12.69% of the city, ISW said.

The analysts said Russian forces failed to capture Kostiantynivka by May 2026 despite deploying additional reinforcements and mechanized equipment. Russian forces sharply intensified offensive operations against Kostiantynivka in March 2026, while Ukrainian officials said Russia’s military command had set a May 2026 deadline to capture the city. As of June 6, Russian forces had brought 80% of the units attacking Kostiantynivka back up to strength.

ISW said Russian forces are likely to make tactical gains in Kostiantynivka in summer 2026, but are unlikely to achieve significant operational success in their effort to seize Ukraine’s fortress belt. Russian troops will likely continue infiltrating Kostiantynivka and consolidating positions in parts of the city, but will suffer heavy losses in the process, the analysts said.

ISW earlier said the presence of Russian forces in Kostiantynivka, Donetsk Oblast, does not indicate that Ukraine’s Defense Forces are encircled in the central part of the city.

DeepState analysts wrote on June 2 that Russia’s infiltration zone in Kostiantynivka was expanding, which could lead to the city’s “inevitable takeover.” The southern and eastern sectors of the city are under active pressure, while the capture of Illinivka and Novodmytrivka threatens northern Kostiantynivka.