The Russians are pouring troops into a key sector just southeast of the town of Dobropillia in eastern Ukraine's Donetsk Oblast, threatening to overwhelm Ukrainian defenses and march one settlement closer to Kramatorsk and Sloviansk, the last two big free cities in Donetsk.

But the Russians' push toward Dobropillia isn't without cost. Russian losses in this sector are "colossal," according to the mapper Playfra. And every soldier the Kremlin deploys along the Dobropillia axis is a soldier it can't deploy elsewhere.

And that may help explain why the Russians are falling back in two other key sectors, in northern Donetsk Oblast and in neighboring Dnipropetrovsk Oblast. The Dobropillia axis is the Russians' clear priority. For the Ukrainians, that's an opportunity to attack elsewhere.

Dobropillia, a former mining town with a pre-war population of around 28,000, is now a fortress. It anchors Ukrainian positions along the highway that threads northeast to Kramatorsk.

Russia has attacked here before. In August 2025, Russian troops pushed a salient toward the Dobropillia–Kramatorsk highway, and Ukrainian counterattacks cut it apart. By October that year, President Volodymyr Zelensky put Russian losses on the Dobropillia front at about 13,000.

Ukrainian military analyst Kostiantyn Mashovets describes the push on Dobropillia as the southern flank of a Russian operation to envelop the whole Sloviansk–Kramatorsk urban area. The other approaches are harder going. From the southeast, the Russians are blocked by stubborn Ukrainian forces still clinging to positions in the ruins of Kostiantynivka. From the north, starting this spring, the Ukrainian 3rd Army Corps rolled back 18 months of Russian gains.

For an army that's been struggling to complete its conquest of Donetsk, to say nothing of breaking through in other front-line oblasts, Dobropillia has become the priority.

And that's why the Russians are channeling fresh forces into the Dobropillia sector. Part of the 41st Combined Arms Army and units of its 90th Guards Tank Division are now fighting there, Mashovets wrote on 9 October, and the Russian command keeps feeding fresh assault infantry into the sector through the village of Nove Shakhove despite heavy losses. The open-source account Unit Observer tracked the buildup as early as September.

Potentially tens of thousands of troops from those formations join the main forces of the 2nd and 51st Combined Arms Armies, according to Mashovets, as well as elements of the Russian naval infantry, facing the Ukrainian 1st Azov Corps and 19th Army Corps around Dobropillia.

The reinforcements give Russian commanders more options. Mashovets expects the 51st CAA to push south and southwest of Dobropillia and the 2nd CAA toward Raksha and Sviatohorivka, enveloping the town and cutting its supply routes from Bilozerske before any direct assault. The neighboring 8th CAA is fighting around Kostiantynivka. The Russians' immediate goal is "to maintain this offensive pressure from summer into the fall," Unit Observer wrote, setting conditions for a possible siege of Kramatorsk next year.

The outlook for the Ukrainian defenders of Dobropillia is "worsening," Playfra warned on 13 October:

The Ukrainians aren't without options, Playfra explained. They should double down on their current strategy of saturating the fields around Dobropillia with drones in a ring at least 2 to 3 km deep, forestalling large-scale Russian movements until the winter strips the leaves off the trees, depriving the Russians of their best cover from overhead surveillance. This could buy Dobropillia "much more time," Playfra predicted.

Mashovets puts a date on how long Dobropillia has to hold. If it and Druzhkivka, the town just south of Kramatorsk, hold until mid-to-late December, he wrote, the whole Russian plan for Sloviansk and Kramatorsk would collapse and have to be rewritten almost from scratch.

Help isn't coming

Just don't expect a lot of Ukrainian reinforcements along the Dobropillia axis. Many of Ukraine's best troops are busy attacking.

Taking advantage of the surge of Russian manpower in the direction of Dobropillia, Ukrainian forces have counterattacked where the Russians are weakest: in northern Donetsk Oblast and also in Dnipropetrovsk Oblast, just south of Donetsk.

In months of carefully planned assaults supported by ground robots and intensive drone strikes, Ukrainian forces have liberated hundreds of square kilometers in northern Donetsk and Dnipropetrovsk. The Ukrainian 3rd Army Corps' Operation Vivaldi in northern Donetsk largely removed the immediate northern threat to Sloviansk and neighboring Kramatorsk.

But it didn't do anything to help in the direction of Dobropillia, where the Russians have many more troops, much more firepower, and—equally importantly—a singular focus: closing the southern jaw around the last big free cities in Donetsk.

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Ukraine's drone pilots are killing and wounding far more Russian infantry than they did a month ago. Ukraine's Unmanned Systems Forces confirmed that their pilots took out 2,699 Russian infantry from 1 to 5 October, 39.7% more than in the first five days of September, Commander Robert "Madiar" Brovdi wrote on Telegram on 6 October.

The Unmanned Systems Forces, the branch of Ukraine's military that fights with drones, count only losses verified by their own pilots in the military's Delta system, so the full picture of Russian losses is larger, Brovdi stressed. Compared with the first five days of August, the rise is 76.5%, from 1,529 losses, which he ties to denser and more frequent Russian assaults.

The sharpest growth occurred in the area of the 1st Azov Corps of Ukraine's National Guard on the Dobropillia-Pokrovsk axis in Donetsk Oblast, as fighting for fortress-belt cities continues. Drone pilots recorded 1,268 Russian losses there, 43% more than the 884 of early September and 91% more than the 664 of early August.

"Russia's hidden mobilization is in action. This is the beginning," Brovdi said ironically.

Russia doubles its monthly recruitment pace

Russian recruitment, mobilization, and contracts run at about 70,000 people a month, twice the 35,000 monthly average from January to August 2026, Brovdi noted on 16 September, when he forecast 12,500 losses for his pilots in September.

He expected the toll to keep climbing. Bigger records still lie ahead because of Russia's unannounced mobilization, Brovdi added on 24 September.

Drone pilots outpaced August by a quarter

September was completed above that forecast. The pilots logged 13,358 Russians killed or wounded, 25.35% more than the 11,010 of August, an average of 445 a day against 355, Brovdi reported. By his count, that equals the full assault infantry of one battalion every day, and his pilots hit a Russian target every 42 seconds.

Two sets of axes took the heaviest toll. In the first 24 days of September, the Dobropillia and Pokrovsk axes accounted for 4,018 losses, and the Oleksandrivka and Huliaipole axes for 3,021, according to Brovdi. The first of those groups covers the same Dobropillia-Pokrovsk axis where the Azov corps zone recorded the sharpest October rise.