Russian forces have intensified assaults on Kostyantynivka in Donetsk Oblast as part of efforts to advance toward the Donbas fortress belt cities including Druzhkivka and Kramatorsk. Daily reports from Ukraine’s General Staff document 15–31 Russian attacks in the sector in recent days, with geolocated footage confirming limited Russian gains in northwestern areas as of early October 2026. Russia claimed full control in July 2026, but Ukrainian units and independent assessments indicate continued fighting and Ukrainian presence inside the city. Ukraine’s Operation Vivaldi counteractions farther north have disrupted Russian flanking maneuvers, while Russian glide bomb strikes and infiltration attempts persist amid heavy drone and artillery use on both sides. Resolution depends on verified territorial control according to established mapping criteria by the market deadline.