KYIV, Ukraine — As Moscow steps up its offensive in eastern Ukraine, weeks of failed attacks on a Ukrainian stronghold have left two Russian brigades in tatters, raised questions about Russia’s military tactics and renewed doubts about its ability to maintain sustained, large-scale ground assaults.
The battle for the city of Vuhledar, which has been viewed as an opening move in an expected Russian spring offensive, has been playing out since the last week of January, but the scale of Moscow’s losses there is only now beginning to come into focus.
Accounts from Ukrainian and Western officials, Ukrainian soldiers, captured Russian soldiers and Russian military bloggers, as well as video and satellite images, paint a picture of a faltering Russian campaign that continues to be plagued by battlefield dysfunction.
In recent weeks, Moscow has rushed tens of thousands more troops, many of them inexperienced new recruits, to the front lines as President Vladimir V. Putin’s forces seek to demonstrate progress before the anniversary of his invasion on Feb. 24. But raising further doubts about Russia’s offensive capabilities, Western officials estimate that a large part of Russia’s army is already fighting in Ukraine.
Britain’s defense secretary, Ben Wallace, told the BBC on Wednesday that “97 percent of the Russian army” is in Ukraine, though he did not elaborate or offer evidence for the claim. U.S. military officials estimate that about 80 percent of Russia’s ground forces are dedicated to the war effort.
The fighting over Vuhledar has come at a cost for Ukraine, too, both in terms of casualties and in the vast amounts of ammunition it has expended to repel Russia’s growing number of ground troops. Kyiv’s allies this week expressed concern about their ability to meet the demand, raising the possibly that Ukrainian commanders might at some point have to limit shelling to the most important targets.
Vuhledar, which sits at the intersection of the eastern front in the Donetsk region and the southern front in the Zaporizhzhia region, has long been in Moscow’s sights. It has been used by Ukraine as a base for harassing shipments on an important rail line supplying Russian forces.
But as has happened in previous Russian offenses, including one in November, “the enemy suffered critical losses,” Col. Oleksii Dmytrashkivskyi, a spokesman for Ukrainian military forces in the area, said in an interview.
He said the attacks on Vuhledar had been no surprise — the Russians even warned the Ukrainians of the coming assault through social media channels, in an apparent attempt to scare them. “It was announced and spread,” Colonel Dmytrashkivskyi said. “It was done to diminish the morale of the fighters.”
As they have done throughout the war, the Russian commanders made some basic mistakes, in this case failing to take into account the terrain — open fields littered with antitank mines — or the strength of the Ukrainian forces, Colonel Dmytrashkivskyi said. Two of Russia’s most elite brigades — the 155th and 40th Naval Infantry Brigades — were decimated in Vuhledar, he said.
In one week alone in the Vuhledar clash, the Ukrainian General Staff estimates, Russia lost at least 130 armored vehicles, including 36 tanks. That estimate has been supported by drone footage reviewed by independent military analysts and by accounts from Russian military bloggers, who are ardent supporters of the war but sharp critics of its conduct by top Russian commanders.
Mr. Wallace, the British defense secretary, cited reports on Wednesday that “a whole Russian brigade was effectively annihilated” in Vuhledar, where he said that Moscow “lost over 1,000 people in two days.” The British Defense Intelligence Agency reported last week that Russian units had “likely suffered particularly heavy casualties around Vuhledar.”
Mr. Wallace told LBC News, a British news outlet, on Wednesday that the losses in Vuhledar showed the result of “a president and a Russian general staff that defies reality or ignores reality and simply doesn’t care how many people they are killing of their own, let alone of the people they are trying to oppress.”
Many of the captured soldiers had been newly mobilized under a call-up Mr. Putin announced in September of some 300,000 recruits, while others had been recruited by the Wagner mercenary group, many of them from prisons, according to Ukrainian and Russian accounts.
In recent weeks, a rivalry between Wagner forces and the regular Russian Army has opened up, with the mercenary group claiming that its fighters are more capable.
Wagner fighters have led the bloody, monthslong Russian campaign to take the city of Bakhmut, 60 miles north of Vuhledar, while the forces in Vuhledar were made up primarily of regular Russian Army units, though some Wagner fighters were present, Ukrainian officials said.
After months of unrelenting Russian assaults in Bakhmut, Ukrainian forces are in an increasingly precarious position, though the Russian gains have come at a heavy cost for Moscow and left Bakhmut in ruins.
The Grey Zone, a Telegram channel that is affiliated with Wagner, has been scathing about the Russian military’s efforts in Vuhledar, and called for Russian commanders responsible for the losses to be held accountable in public trials. “Impunity always breeds permissiveness,” a recent post said.
After Russia’s November attack on Vuhledar, which was also reported to have ended with enormous losses, Moscow turned to newly mobilized recruits to replenish its ranks. But those troops had just a bare minimum of training, military analysts say, and probably not enough to mount a serious, organized offensive.
The Russians faced another problem in Vuhledar from Ukraine’s deployment of American-made HIMARS missiles that forced commanders to position large concentrations of forces more than 50 miles from the front. That made it hard to attack with either speed or surprise.
A Russian marine who fought in Vuhledar told the Russian media outlet 7x7, which is based in the Komi region of Russia, that those who survived the battle were considered deserters. The marine, whose identity the news outlet did not disclose, citing the need to protect his safety, said he was part of the third company of the 155th brigade. After the failed assault, he said, only eight soldiers from his company were left alive.
“It would have been better if I had been captured and never returned,” he said.
Despite the setbacks, Moscow has continued to insist that all is going according to plan. On Sunday, Mr. Putin said that the “marine infantry is working as it should. Right now. Fighting heroically.”
For the moment, Colonel Dmytrashkivskyi said, the large-scale Russian assaults have subsided, though the Russians are still attacking in small bands of 10 to 15 soldiers, probably probing Ukrainian defenses for weaknesses.
If the Russians continue with that tactic, he said, they will be outnumbered by Ukrainian platoons of 30 soldiers.
“They are going to their death, and that’s it,” he said.