Tired Ukrainian Troops Fight to Hold Back Russian Offensive: ‘They Come Like Zombies’

But more Russians keep coming. Depleted Ukrainian units can’t shoot them all.

“Step by step, they take our positions," said Lt. Oleksandr Shyrshyn, deputy commander of an understrength battalion of Ukraine’s 47th Mechanized Brigade that is defending a kilometer-long stretch of the front.

The Russian army is accepting heavy casualties as the price of inching forward. For weeks it has thrown tens of thousands of troops at Avdiivka, a shell-scarred industrial city in the Donetsk region of eastern Ukraine. Russia’s effort to encircle the town has become this fall’s biggest battle in President Vladimir Putin’s war to subjugate Ukraine.

Capturing Avdiivka could open up further local advances for Russia in Donetsk. It would also be a propaganda win for Putin, allowing him to claim that momentum in the war is back with Moscow.

This summer, Ukraine had hoped to take back swaths of the nearly 20% of the country that Russia currently occupies. But Russia’s well-fortified lines mostly held firm against the counteroffensive. Ukraine pounded Russian troops and logistics but used up several brigades and much Western-supplied ammunition without achieving the territorial breakthrough it wanted.

Even before Ukraine’s offensive wound down, Russia gathered reserves for its own renewed push on the eastern front.

The battle for Avdiivka could mark the beginning of many months on the defensive for Ukraine. With the U.S. in the grip of partisan paralysis and Europe struggling to boost military production, the uncertain supply of Western ammunition limits what Kyiv’s army can now attempt. Meanwhile, Moscow smells weakness.

Russia’s first attacks on Avdiivka in October failed. Columns of tanks and armored troop carriers fell prey to mines, drones and artillery. The Russians changed tactics, sending waves of infantry forward in small groups. The shift echoed Ukraine’s own switch to foot tactics in its summer offensive after losing too many armored vehicles.

Both armies are struggling to maneuver on open, mined terrain beneath skies buzzing with drones. The difference: Russia, with a population nearly four times Ukraine’s, can afford to lose untold thousands of soldiers for small gains.

Russia’s massive losses in the nearly two-year war have left its ground forces reliant on old vehicles and poorly trained conscripts, limiting its offensive potential, for now, to grinding assaults on small cities. Russia lost tens of thousands of men in the 10-month battle for Bakhmut, its last notable victory.

Meanwhile, Ukraine is struggling to replace its infantry losses in the summer counteroffensive and the costly defense of Bakhmut. Ukrainian casualty numbers are a tightly kept secret, but fresh graves and full hospitals around the country testify to the heavy toll.

Ukrainian front-line units are commonly 20% to 40% below full strength, said Ihor Romanenko, a military analyst and retired Ukrainian lieutenant general. “Because of the shortage of infantry, those remaining are tired," he said. There is little scope for rest or rotation.

Avdiivka has long been a thorn in the side of Russian forces in eastern Ukraine. The fortified town forms a salient north of Donetsk city, limiting Russian control of the region. Ukrainian troops have held off Russian attacks here since 2014, when Moscow launched a covert invasion of Ukraine’s east. Only around 1,400 residents remain in Avdiivka, once home to more than 30,000.

Russian troops have surrounded Avdiivka on three sides and have taken the only high ground in the area, a broad slag heap to the northeast, using it to keep Ukrainian armor at bay with antitank missiles. Waves of Russian infantry are trying to assault Avdiivka’s sprawling coke plant and have entered the city’s southeastern outskirts.

“We’re still motivated, but we’re exhausted," said Pvt. Oleksandr Siergeichikov, who has been defending Avdiivka since the spring of 2022 with Ukraine’s 110th Mechanized Brigade. He described how Russian infantry took the slag heap by crawling over the bodies of their comrades until the Ukrainian defenders ran out of firepower.

The Russians’ plan is to push further past Avdiivka to the north and south, then cut off its supply roads. Avdiivka’s lifeline has shrunk to a gap of less than 4 miles between the jaws of the Russian advance.

The attacking Russian infantry are mostly poorly trained, often bunching up and making easy targets, say Ukrainian soldiers fighting here.

“They come like zombies. Some wear headlamps—a happy moment for any machine-gunner," said Pvt. Bohdan Lysenko, who mans the 25 mm automatic cannon on a U.S.-made Bradley Fighting Vehicle with the 47th Brigade.

Drone images show fields littered with the bodies of Russian infantry hit by artillery, including U.S.-supplied cluster munitions. But the Russians keep coming.

“They’re not stupid. It’s a strategy," said Cpl. Mykhailo Kotsyurba, a Bradley commander in the same company as Lysenko. “They look for weak points, then go there. We don’t have enough ammunition, but they have enough people."

Some Russians give themselves up rather than continue with near-suicidal assaults. They often say they walked into Ukrainian positions by accident. Voluntary surrender is a crime in Russia.

“Our commanders, despite the circumstances, are given orders to take positions that are impossible to hold. That’s why we have such losses among the ordinary soldiers," said Andrei Bednyaev, an infantryman from Russia’s 114th Guards Motor Rifle Brigade. “They treat us as waste material."

Bednyaev, who volunteered to speak to The Wall Street Journal in a makeshift Ukrainian holding facility, said he was captured while disoriented after an exploding drone blasted a brick wall at him.

The 47th Brigade, formed to take part in Ukraine’s counteroffensive, was trained by U.S. troops in Germany, armed with Bradleys and German-made Leopard 2 tanks, and thrown at Russia’s densely mined lines in the southern Zaporizhzhia region this summer. The slow pace of Western arms deliveries had given the Russians many months to prepare their defenses. Poor planning, reconnaissance and coordination also cost the Ukrainians, say troops who fought in the offensive. In August, the 47th took part in the capture of Robotyne, the only breach in the Russian’s main fortified line. But the brigade was exhausted and needed rebuilding.

In October, the 47th was sent to shore up the defense of Avdiivka. When the Russians saw their Bradleys and Leopards, they moved more drone units to the area to counter them.

Lt. Shyrshyn’s battalion, once made up of highly motivated volunteers, now relies mostly on briefly trained conscripts. The unit compensates by using its Bradleys in a mobile defense. “Here you can use the potential of Bradleys more effectively than in Zaporizhzhia, where it was impossible to maneuver."

North of Avdiivka, the Russians have crossed a fiercely contested railroad track and now need to capture the villages of Stepove and Berdychi to progress. Soldiers fight and die to control the tree lines crisscrossing the abandoned farmland, where Ukraine’s fertile black soil is covered in craters.

A layer of cold mud clings to roads, vehicles and troops. The first winter snow is falling. Shells whistle high overhead.

A Russian special assault unit recently stormed some of the houses in Stepove. A Ukrainian Bradley raced up and down the street, pulverizing the houses with its cannon. “This is the best vehicle I have ever seen," said Shyrshyn, rewatching the drone footage. Some Russians fled into a basement. A Ukrainian drone followed them inside and detonated its payload.

Shyrshyn grew up in Crimea speaking Russian but left after Moscow annexed the peninsula in 2014. “I saw troops on the streets and Putin lying about it on TV, and I understood that they are not our brothers," he said. He switched to speaking Ukrainian and joined the army on Feb. 24 last year, the day Russia launched its full-scale invasion.

The 47th tries to cancel Russian advances with counterattacks. Their tactics, ordered from on high, often rely on costly frontal assaults. Kotsyurba and Lysenko’s unit was ordered to retake a lost tree line with six Bradleys, each carrying six infantrymen. Reconnaissance on the Russians’ numbers was limited. The enemy also held a perpendicular tree line, so that the Ukrainian assault would be under fire from the flank. “I told the general the plan was unrealistic," said Kotsyurba.

Lysenko judged from experience that the attack would end in a slaughter. He refused to take part and was fined a month’s salary and bonus. “I paid 120,000 hryvnias for my life," he said of the sum, equivalent to $3,300.

The assault went ahead regardless, with the Bradleys unloading their troops at the tree line under heavy fire. The trenches contained far more Russians than expected. Their machine guns and grenades killed 17 of the Ukrainian infantry. The rest escaped in Bradleys that bore scars from rocket-propelled grenades.

Kotsyurba and Lysenko’s company began the summer with 120 men. It’s now down to around 20, including replacements. The rest are dead, wounded or have been transferred away from assault duties. The new faces are mostly over 40 years old, some in poor health.

Many veterans of the 47th blame Ukraine’s struggles this year on Soviet-style commanders whose rigid tactics have thinned their Western-trained ranks.

“We don’t have a chance playing war-of-exhaustion with Russia," said Lysenko. “We need a fundamental change in our army."

Write to Marcus Walker at Marcus.Walker@wsj.com