Russia Tries to Split Kostiantynivka as Ukraine Pulls Back From the Center

The battle for Kostiantynivka, one of the largest battles of Russia’s war in Ukraine, appears to be entering its final phase, according to OSINT analysts and military experts. Russian forces began their assault on the city in November, but analysts say a full capture may still take more than a month.

After four months of trying to enter the suburbs, Russian troops have begun pushing deeper into the city, French OSINT analyst Clement Molin wrote on Monday.

According to the OSINT project Playfra, Russian forces found a weak point in Ukrainian defenses southwest of Kostiantynivka, near the village of Illinivka and the settlement of Berestok. The advance came at a high cost, but gave Russian units a chance to move forward more steadily.

The OSINT project AMK Mapping said Ukrainian troops had started withdrawing from the city center toward the northwestern suburbs because of the threat of encirclement from the flanks.

Some Ukrainian units may already be in operational, and possibly full, encirclement in parts of the city, the project said.

Fighting is continuing in several districts, especially in eastern Kostiantynivka, according to Molin. He wrote that Ukrainian forces still maintain a presence across almost the entire city, while Russian and Ukrainian positions are often detected in the same neighborhoods.

Playfra made a similar assessment last week, saying Ukrainian forces still had a clear advantage in the number of controlled positions across the city at any given moment.

A representative of Conflict Intelligence Team, speaking to Agentstvo on condition of anonymity, described the situation as extremely difficult. Russian troops have advanced deep to the west and east of the city and have begun entering the center, trying to split Kostiantynivka in two.

According to the CIT representative, they have been more successful in the western part of the city.

Russian forces are trying to surround Ukrainian positions and force a gradual retreat, Playfra wrote.

Molin compared the tactic to last year’s battle for Pokrovsk: after failing to cut the city’s supply routes, Russian troops are trying to establish themselves inside built-up areas near those routes and pressure Ukrainian forces to withdraw step by step.

Kostiantynivka, whose prewar population was about 65,000, sits at the southern edge of the Donbas “fortress belt” — a 45-kilometer line of heavily fortified towns and smaller settlements. It is one of the last major Ukrainian defensive lines in the region.

Molin described the battle as one of the largest of the war, alongside the assault on Bakhmut from August 2022 to May 2023, the battle for Toretsk from summer 2024 to summer 2025, and the continuing battle for Chasiv Yar.

If Russia captures Kostiantynivka, the city could become a staging area for an attack on nearby Druzhkivka, the CIT representative said. He compared the significance of its possible loss to the fall of Pokrovsk.

How long the battle will last is still unclear. The CIT representative said he did not expect Russia to fully capture the city within the next month. Playfra estimated that fighting for Kostiantynivka would probably continue until the end of the summer.

OSINT analyst Kirill Mikhailov told Agentstvo that after Kostiantynivka falls, fighting could eventually shift to Druzhkivka, about 15 kilometers away.

At the current pace, he said, that battle could last at least until 2027.

Druzhkivka, like Kostiantynivka, is one of the four largest cities in the part of Donbas still controlled by Ukraine and forms part of its urban defensive belt.

But Playfra noted that Druzhkivka has somewhat fewer fortifications.

The next phase of Russia’s offensive is unlikely to be simple. Ukrainian positions near Chasiv Yar still prevent Russian forces from taking direct control of the high ground overlooking the valley, one expert said.

For Moscow, the broader goal remains the capture of the rest of Donetsk region. Vladimir Putin has described that objective as one of Russia’s current aims in the war.