Russian forces have conducted sustained offensive operations against Kostyantynivka in Donetsk Oblast since late 2025, achieving incremental tactical gains and limited infiltrations into eastern and central districts through mid-2026 while missing earlier deadlines for full seizure. Ukrainian defenders have repelled repeated assaults on the axis, with the General Staff reporting 18–28 daily attacks in September–October 2026 amid continued fighting in surrounding areas such as Illinivka and Oleksiievo-Druzhkivka. Russia announced full capture in early July 2026, a claim rejected by Ukrainian officials who reported clearing central positions and maintaining control of key sectors. The city anchors the southern end of Ukraine’s fortress belt defensive line protecting routes toward Kramatorsk and Sloviansk, where Russian forces have also applied pressure through strikes and advances. Ongoing attrition, logistics challenges, and Ukrainian counteractions in the gray zone continue to shape assessments of any timeline for complete Russian control.