Russian forces continue incremental infiltration tactics into Kostyantynivka, a key southern anchor of Ukraine’s Donetsk “fortress belt,” amid broader efforts to advance toward Sloviansk and Kramatorsk. As of late September 2026, Ukrainian units repelled 25 Russian assaults near the city and surrounding settlements including Mykolaipillia and Illinivka, while Ukraine’s Third Army Corps reported territorial gains north of Lyman that disrupt Russian encirclement attempts. Control remains contested in gray-zone areas, with Russian progress slowed by Ukrainian counterattacks and logistics challenges. Upcoming factors include seasonal weather effects on drone operations and any shifts in manpower or strikes that could alter frontline momentum in the Donbas.