Key developments:
150,000 Russian troops massing around Pokrovsk
5 Russian brigades redeployed from Sumy front
156th Mechanized Brigade rushing south as reinforcement
Russia’s first major tank-led offensive in months
The Ukrainian army stood up the 156th Infantry Brigade in the spring of 2024. Not long after, the unit converted into a mechanized brigade with additional armored vehicles.
The brigade recruited and trained its thousands of troops through the fall and winter and, this summer, deployed to the front line in Sumy Oblast in northern Ukraine.
Now the 156th Mechanized Brigade is one of the growing number of Ukrainian units rushing south to Donetsk Oblast to meet a mass of Russian troops and tanks poised to strike at the fortress city of Pokrovsk for what Ukrainian drone operator Kriegsforscher described as a “last, final battle.”
As recently as last month, the 156th Mechanized Brigade was helping to hold the line in Sumy alongside other brigades in the new 18th Army Corps. But with the defeat of its infantry-led incursion northeast of Pokrovsk in recent weeks, the Kremlin made a portentous decision.
Rather than give up on Pokrovsk, it doubled down—and surged reinforcements around the city for what’s shaping up to be a powerful, tank-led offensive.
Pokrovsk’s fall would open the path to Ukraine’s last major defensive positions in Donetsk, potentially forcing a strategic withdrawal that could reshape the entire eastern front.
The reinforcements had to come from somewhere. No fewer than five Russian marine and airborne brigades and regiments plus a tank regiment, an infantry regiment, and two motor rifle brigades have redeployed—or are in the process of redeploying—from Sumy to the sector around Pokrovsk.
These fresh forces, plus a motor rifle division redeploying from Kherson Oblast in the south, amount to the equivalent of an entire field army. They join the eight or so Russian field armies already laying siege to Pokrovsk and nearby towns.
There may be 150,000 Russian troops massing around Pokrovsk. And they’re bringing in large numbers of tanks and other armored vehicles for the first time in many months.
Throughout 2025, Russian regiments have mostly attacked on foot or on motorcycle. Now it’s clear why. “Slowly but surely, it’s being proven that Russia was indeed holding back armor in the rear and reducing mechanized attacks to the bare minimum,” analyst Jompy noted.
Russian commanders were saving their armored vehicles for something. That something, it seems, is the biggest—and potentially last for a while—mechanized assault on Pokrovsk, the last major strongpoint between the Russians and main Ukrainian “fortress belt” threading through Kramatorsk and Sloviansk in western Donetsk.
Russia’s largest armored assault in months
The coming clash “will be bigger, bloodier” than the infantry battles that were common around Pokrovsk earlier this year, Finnish analyst Joni Askola warned. It will fall on newly arriving units such as the 156th Mechanized Brigade to hold off a much larger Russian force.
The 156th Mechanized Brigade hit the road to Donetsk last month, according to Unit Observer. It joins the national guard’s 1st Azov Corps and adjacent units that rushed toward Pokrovsk in early August to block, and then roll back, that Russian infantry incursion that briefly threatened one of the two remaining main supply lines into Pokrovsk.
Other Ukrainian units currently in Sumy could follow the 156th Mechanized Brigade to Donetsk as more Russian troops quit Sumy and head south for the coming push on Pokrovsk. The next round of Ukrainian reinforcements could include the 80th and 95th Air Assault Brigades.
Compared to those elite air assault formations, the 156th Mechanized Brigade is a workmanlike unit. It rides in T-64BV tanks, BMP-1TS with new 30-millimeter autocannon turrets, M-113 tracked armored personnel carriers, upgraded BTR-60D wheeled APCs, Kozak armored trucks and M-109 howitzers. Many of these vehicles sport add-on anti-drone armor.
Ukraine’s tank-killing strategy faces its biggest test
Expect the 156th Mechanized Brigade to dig in and prepare for tank attacks. The older Ukrainian brigades around Pokrovsk are skilled tank-killers, but the 156th Mechanized Brigade’s relatively green troopers should be able to pick up the standard tactics fairly quickly.
In the 43 months since Russia widened its war on Ukraine, Ukrainian forces have destroyed, damaged or captured around 4,100 Russian tanks. That’s more tanks than Russian regiments had in front-line service before the wider war.
They took out those tanks with mines, artillery, anti-tank missiles and—perhaps most importantly—explosive first-person-view drones and grenade-dropping bomber drones. The Russians are betting that tank-led assaults can help them win the battle for Pokrovsk. The Ukrainians are betting they can blow up the tanks in the usual way.
Russia’s tank reserves running dangerously low
If the Russians can’t break through the reinforced Ukrainian defenses around Pokrovsk in the coming months, they might not get another chance anytime soon—at least not with tanks.
Russia’s Uralvagonzavod tank factory is building new T-90Ms—but it’s unclear how many. The factory’s output may have collapsed this year. Meanwhile, the Kremlin’s vehicle storage bases, once brimming with Cold War leftovers, are now mostly empty of usable vehicles.
