Ukrainian military medics carry an injured Ukrainian serviceman evacuated from the battlefield into a hospital in Donetsk region, Ukraine, on Monday. The serviceman did not survive. Evgeniy Maloletka/Associated Press

KYIV, Ukraine — Russian forces are escalating their onslaught against Ukrainian positions around the wrecked city of Bakhmut, Ukrainian officials said, bringing new levels of death and devastation in the grinding, monthslong battle for control of eastern Ukraine that is part of Moscow’s wider war.

“Everything is completely destroyed. There is almost no life left,” Ukrainian President Volodymyr Zelensky said late Monday of the scene around Bakhmut and the nearby Donetsk province city of Soledar, known for salt mining and processing.

“The whole land near Soledar is covered with the corpses of the occupiers and scars from the strikes,” Zelensky said. “This is what madness looks like.”

Late Tuesday, the head of the Wagner Group, a Russian private military contractor, Dmitry Prigozhin, claimed in audio reports posted on his Russian social media platform that his forces had seized control of Soledar, with battles continuing in a “cauldron” in the city’s center. Ukrainian officials did not comment on the claim, and The Associated Press was unable to verify it.

The U.K. Defense Ministry said earlier that Russian troops alongside soldiers from the Wagner Group had advanced in Soledar and “are likely in control of most of the settlement.”

The ministry said that taking Soledar, 6 miles north of Bakhmut, was likely Moscow’s immediate military objective and part of a strategy to encircle Bakhmut. But it added that “Ukrainian forces maintain stable defensive lines in depth and control over supply routes” in the area.

A Western official, speaking on condition of anonymity, said the Wagner Group “has moved from being a niche sideshow of Russia’s war to a major component of the conflict,” adding that its forces now make up as much as a quarter of Russian combatants.

The Kremlin, whose invasion of its neighbor 10 1/2 months ago has suffered numerous reversals, is hungry for victories. Russia illegally annexed Donetsk and three other Ukrainian provinces in September, but its troops have struggled to advance.

After Ukrainian forces recaptured the southern city of Kherson in November, the battle heated up around Bakhmut.

Smoke billows after Russian attacks in the outskirts of Bakhmut, Ukraine, on Dec. 27. Libkos/Associated Press

Ukraine’s deputy defense minister, Hanna Malyar, said Russia has thrown “a large number of storm groups” into the fight for the city. “The enemy is advancing literally on the bodies of their own soldiers and is massively using artillery, rocket launchers and mortars, hitting their own troops,” she said.

Pavlo Kyrylenko, the Donetsk region’s Kyiv-appointed governor, on Tuesday described the Russian attacks on Soledar and Bakhmut as relentless.

“The Russian army is reducing Ukrainian cities to rubble using all kinds of weapons in their scorched-earth tactics,” Kyrylenko said in televised remarks. “Russia is waging a war without rules, resulting in civilian deaths and suffering.”

Wounded soldiers arrive around the clock for emergency treatment at a Ukrainian medical stabilization center near the front line around Bakhmut. Medics fought for 30 minutes Monday to save a soldier, but his injuries were too severe.

Another soldier suffered a head injury after a fragment pierced his helmet. Medics quickly stabilized him enough to transfer him to a military hospital.

“We fight to the end to save a life,” Kostyantyn Vasylkevich, a surgeon and the center’s coordinator, told The Associated Press. “Of course, it hurts when it is not possible to save them.”

The Moscow-backed leader of the occupied areas of Donetsk, Denis Pushilin, told Russian state TV control over the city would create “good prospects” for taking over Bakhmut, as well as Siversk, a town further north where Ukrainian fortifications “are also quite serious.”

An exceptional feature of the fighting near Bakhmut is that some of it has taken place around entrances to disused salt mine tunnels which run for some 200 kilometers (120 miles), the British intelligence report noted.

“Both sides are likely concerned that (the tunnels) could be used for infiltration behind their lines,” it said.

In Russia, two signs emerged Tuesday that officials were grappling with the military shortcomings revealed during the conflict in Ukraine.

Russian Defense Minister Shoigu, whose performance has been fiercely criticized in some Russian circles but who has retained Russian President Vladimir Putin’s confidence, said Tuesday that his military would use its experience in Ukraine to improve combat training.

Military communications and control systems will be improved using artificial intelligence, Shoigu said, and troops will be given better tactical gear and equipment.

The second indication of trouble involves Russia’s production of weapons and other supplies its military needs for the fight in Ukraine. The deputy head of Russia’s Security Council, Dmitry Medvedev, warned that officials who failed to meet deadlines for such items could face criminal charges.

Putin appointed Medvedev last month to head a new commission tasked with trying to solve the military’s supply problems. Numerous reports have suggested Russia is running low on certain weapons and was sending some troops into battle with insufficient equipment and clothing.

Part of the Kremlin’s challenge is keeping up with the weapons and supplies that Western allies are providing to Ukraine.

The Patriot surface-to-air guided missile defense system is one of the weapons Ukraine is about to receive, and the Pentagon announced Tuesday that about 100 Ukrainian troops will head to Oklahoma’s Fort Sill as soon as next week to begin training on it. That will help Ukraine protect itself against Russian missile attacks. The United States pledged one Patriot battery last month, and Germany has pledged an additional system.

Germany’s foreign minister, Annalena Baerbock, announced Tuesday while visiting Ukraine’s second largest city, Kharkiv, that her country would also provide 40 million euros ($43 million) to help with demining, energy infrastructure and internet connections, German news agency dpa reported.

Several front-line cities in eastern Ukraine’s Donetsk and Luhansk provinces have witnessed intense fighting in recent months.

Together, the provinces make up the Donbas, a broad industrial region bordering Russia that Putin identified as a focus from the war’s outset and where Moscow-backed separatists have fought since 2014.

Russia’s grinding eastern offensive captured almost all of Luhansk during the summer. Donetsk escaped the same fate, and the Russian military subsequently poured manpower and resources around Bakhmut.

Taking Bakhmut would disrupt Ukraine’s supply lines and open a route for Russian forces to press toward Kramatorsk and Sloviansk, key Ukrainian strongholds in Donetsk.

Like Mariupol and other contested cities, Bakhmut endured a long siege without water and power even before Moscow launched massive strikes to take out public utilities across Ukraine.

Kyrylenko, the Donetsk region’s governor, estimated more than two months ago that 90% of Bakhmut’s prewar population of over 70,000 had fled since Moscow focused on seizing the entire Donbas.

Ukraine’s presidential office said at least four civilians were killed and another 30 wounded in Russian shelling between Monday and Tuesday.

Vitaliy Kim, the governor of the southern Mykolaiv region, said Russian forces shelled the port of Ochakiv and the area around it late Monday and again early Tuesday. He said 15 people, including a 2-year-old child, were wounded.