On July 3, 2026, russian Chief of the General Staff Valery Gerasimov briefed President Vladimir Putin that russian forces had fully captured Kostiantynivka, a key urban centre in Donetsk region within the Ukrainian fortress belt, according to the UK Defence Intelligence.
Russia had first attempted to seize the city in summer 2025. It is highly unlikely that russia has fully secured Kostiantynivka. Instead, it is assessed that russia likely occupies approximately over half of the urban centre.
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Open source reporting has identified incidents of russian flag raising along the northern boundary of the city, but these are highly likely small infiltration groups rather than a consolidated force. This tactic has been used previously in urban centres such as Kupiansk and Siversk as part of russia's information operations campaign.
It is highly likely that Ukraine continues to defend the city, disrupting russia's ability to seize full control.
The capture of Kostyantynivka would be militarily significant due to its ability to act as a launchpad for russia's assault on the remaining fortress belt cities of Druzhkivka, Kramatorsk and Sloviansk.
However, each of the fortress belt cities are robustly fortified with Ukrainian defensive positions. Continued russian assaults on these cities will highly likely come at high cost for russian forces.
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