Russian forces have conducted a grinding offensive against Kostiantynivka since October 2025 as part of efforts to pressure Ukraine’s Donbas defensive line, achieving incremental infiltration into eastern and central districts through small assault groups and glide bomb strikes. Ukrainian units have contested these advances, conducting clearance operations that removed Russian elements from central areas in July 2026 and repelling repeated attacks amid ongoing daily engagements in the sector as of early October 2026. Ukrainian commanders report that attempts to encircle the broader fortress belt cities have been disrupted, with high Russian losses in the direction limiting rapid consolidation. Control remains fragmented per assessments from the Institute for the Study of War, with Russian forces holding positions inside the city but facing mined approaches and reinforced Ukrainian defenses that constrain further gains.