Russian claim to have taken Kostiantynivka disputed

British Defence Intelligence has assessed that Russian forces have not fully captured Kostiantynivka in Donetsk oblast, despite the head of Russia’s General Staff telling President Putin earlier this month that the city had fallen, the Ministry of Defence stated in an intelligence update posted to X.

The briefing to Putin was delivered by Valery Gerasimov on 3 July. According to the assessment, it is highly unlikely that Russia has fully secured the city, with Russian forces instead judged likely to hold somewhat over half of the urban centre. Russia first attempted to take Kostiantynivka in the summer of 2025.

Defence Intelligence points to open source reporting of Russian flag raising along the northern edge of the city, which it assesses as highly likely to be small infiltration groups rather than a consolidated force. The update notes the same tactic has been used at Kupiansk and Siversk as part of a Russian information operations campaign. Ukrainian forces are judged highly likely to be continuing to defend the city and to be disrupting Russian efforts to take full control.

Kostiantynivka forms part of what is known as the fortress belt, the chain of fortified Ukrainian urban positions running through Donetsk oblast that has anchored the defence of the region since 2014. The assessment describes the city’s capture as militarily significant because it would provide a launchpad for assaults on the remaining fortress belt cities of Druzhkivka, Kramatorsk and Sloviansk. Each of those, Defence Intelligence states, is robustly fortified, and continued Russian assaults against them are judged highly likely to prove costly.

The wording of these assessments is deliberate as Defence Intelligence uses a probability yardstick developed in the early 2000s and now applied across the UK intelligence community, splitting likelihood into seven bands with a set term attached to each. Phrases such as “highly unlikely” and “highly likely” therefore correspond to defined numerical ranges rather than to loose description, and the scale is intentionally non-continuous to avoid implying a precision the underlying evidence does not support.

Kostiantynivka sits south of Kramatorsk on the road running north from Bakhmut, which Russian forces captured in May 2023 after a battle lasting the better part of a year. The city held a pre-war population of around 67,000 and has been within artillery range of the front for an extended period, with civilian evacuation ordered progressively as the line moved closer. Sloviansk and Kramatorsk, the two largest cities of the belt, have been objectives of Russian planning since the earliest weeks of the full-scale invasion, and both were briefly held by Russian-backed forces in 2014 before being retaken by Ukraine.

Claims of captured settlements have been a recurring feature of the war, with Russian announcements frequently preceding actual control by weeks or failing to materialise. Ukrainian officials have similarly been accused of understating losses of ground.

Independent verification usually relies on geolocated imagery, which typically lags the fighting.