Inside the Battle of Kostiantynivka, as Ukrainian forces brace for three-sided Russian assault

"Kostiantynivka is the southern and easternmost of an agglomeration of four cities that form the logistical spine of Ukraine’s defense of Donetsk Oblast: connected to the city by a key highway is Druzhkivka to the north, followed by Kramatorsk and finally Sloviansk.
With its streets emptied of almost all life, the battle for Kostiantynivka has begun in earnest: together with nearby Pokrovsk, the city is a major roadblock for Moscow’s ambitions to take all of Donetsk Oblast.
As of August 2025, Russian forces have come within around six kilometers of the city’s outskirts, according to open-source mapping project DeepState.

Though the saturation of the sky with strike drones on both sides has been a feature of the battlefield in Ukraine for over a year, this spring brought a new seismic shift to this part of the front line: the arrival of the elite Russian drone unit Rubicon.
While also operating standard radio first-person view (FPV) drones, Rubicon specializes in the use of long-range fiber optic FPVs, designed to reach and consistently strike Ukrainian targets deeper in the rear than was understood to be possible.
For Ukrainian brigades fighting in the area, the arrival of the Rubicon drone teams has been a challenge like no other, forcing a complete rethink of their front-line logistics chains. Some have managed better than others.
Meanwhile, Ukraine’s own top drone units have done the same, targeting every part of the Russian logistics chain and making vehicle-based attacks and logistics next to impossible.
The result: a deterioration of the concept of coherent front lines, replaced by a grey zone between the two sides that gets deeper and deadlier with every month.
As of August 2025, Ukraine’s larger salient around Kostiantynivka is made up of a string of sectors, each acting as both its own battle with its own unique terrain and as part of an interconnected line of defense.
In the northeast is Chasiv Yar, which Russian forces claimed to complete the capture of on July 31. Kyiv has so far denied the claim, but open source mapping projects all point to the vast majority of the ruined city now being under Russian control.
Running south of Chasiv Yar toward Toretsk, Ukrainian lines have held firm along the canal for over a year, but recent Russian advances have breached this natural defense, pushing to within eight kilometers of Kostiantynivka.
Ukraine’s defense remains stable in the city of Toretsk itself, while Liubart, together with the Azov Brigade itself as part of Ukraine’s new 1st National Guard Corps, is holding the sector just west of the city, defending both sides of a large reservoir and the high ground behind it.
The main threat now to Kostiantynivka is coming from the southwest, where a fresh Russian offensive push in spring punched across the T0504 highway, exploiting a weak link in Ukraine’s defense manned by less combat effective brigades." 

KI