The last major city held by Ukraine in the heavily contested eastern province of Luhansk has fallen, military officials on both sides said Sunday, giving Moscow a milestone victory in its campaign to capture the Donbas, the mineral-rich region bordering Russia that has long been in President Vladimir V. Putin’s sights.
The industrial city of Lysychansk, on a rise overlooking the Siversky Donets River, had held out for a week after Russia seized control of Sievierodonetsk, its twin city across the river. But as Russia inundated Lysychansk with artillery fire and strangled its supply lines, building on months of bombardment and weeks of ferocious street fighting that reduced both cities to grayed-out husks, Ukrainian defenders were forced to retreat.
That left Russian soldiers posing for pictures outside Lysychansk City Hall, chanting, “Lysychansk is ours” and waving the flag of the Donetsk People’s Republic — the pro-Moscow separatist state that Mr. Putin claimed to be protecting when his forces invaded Ukraine, a video posted on Twitter on Sunday showed.
Western military analysts had expressed little doubt that Moscow would eventually prevail in the twin cities, but with their loss undeniable, pressure redoubled on the United States and its allies to get the more powerful weapons they have promised Ukraine to the front. For nations in the West, however, the next phase of the war will prove a test not just of military logistics but of solidarity. As the conflict drags on, their own citizens are feeling the economic pain, and unity among the allies may be difficult to sustain.
Russia now faces new challenges of its own. It controls more than a fifth of Ukraine — much of it cities in name only, skeletal remains emptied of people after months of shelling — but it will need to replenish depleted forces and ammunition as it wages what promises to be a fierce, drawn-out ground war.
On Sunday, Ukraine’s president, Volodymyr Zelensky, denied that Lysychansk was completely in Russian hands. At a news conference with Australia’s prime minister, who was visiting Kyiv, Mr. Zelensky said fighting was taking place on the outskirts of the city.
But videos posted on social media appeared to show Russian troops in the city center, and residents who fled the region in recent days said the bulk of the Ukrainian forces in Lysychansk left on Friday.
Hours after Russia’s military proclaimed victory in the city, the Ukrainian military acknowledged that it had pulled out its forces there. “The continuation of the defense of the city would lead to fatal consequences,” it said in a statement on Facebook. “In order to preserve the lives of Ukrainian defenders, a decision was made to withdraw.”
With Luhansk Province now in hand, Russian forces can aim squarely southwest at the remaining Ukrainian-held parts of the neighboring province of Donetsk, the other territory that makes up the Donbas.
Better Understand the Russia-Ukraine War
Control of the Donbas, Ukraine’s industrial heartland, has become Moscow’s chief target since it failed to take Kyiv, the capital, this spring. The Donbas would be a prize offering Russia not only mineral resources but also an overland corridor to Crimea, the Black Sea peninsula it annexed by force in 2014.
Russia’s defense minister, Sergei K. Shoigu, said that the Russian Army, as well as units of the Luhansk People’s Republic, a second pro-Moscow separatist government, had established “full control over the city of Lysychansk and a number of nearby settlements,” according to a Russian Defense Ministry statement.
On Saturday, the Institute for the Study of War, a Washington-based research group, published an assessment that reinforced Russia’s claims. “Ukrainian forces likely conducted a deliberate withdrawal from Lysychansk, resulting in the Russian seizure of the city,” the institute said. Videos showing Russian forces casually walking around suggested there were few or no remaining Ukrainian troops, it said.
After eight years of war between Moscow-backed separatists and Ukraine in the country’s east, Russia already controls between one-half and two-thirds of Donetsk Province. Now Russia is expected to use Lysychansk to grind into Donetsk with offenses on the cities of Sloviansk, Kramatorsk and Bakhmut to Lysychansk’s southwest, all but assuring that the next chapter of the war will be as bloody as the last.
Already, Ukrainian defensive lines were shifting west to Bakhmut, a key supply hub where Russia has applied greater pressure with artillery and cruise missile fire in recent days. Farther west in Sloviansk, the mayor, Vadym Lyakh, reported on Sunday the heaviest Russian shelling yet on the city. Six people were killed and 15 wounded, he wrote on Facebook, and at least 15 buildings were on fire.
One Lysychansk resident, Ivan Shybkov, who fled to western Ukraine last month after helping evacuate civilians, described what was happening as “a knife to the heart” — particularly images of some people in Lysychansk greeting the invaders “with smiles on their faces” after long months without basic services like water, electricity, cellphone service and internet.
“Our emotions are not a switch that can be switched off,” Mr. Shybkov said. “Therefore, of course, it hurts us a lot.”
In the battle for Sievierodonetsk and Lysychansk, Moscow pursued a more successful strategy than in the initial phase of the invasion, when analysts say it spread its forces too thinly while trying to capture Kyiv and Ukraine’s second-largest city, Kharkiv.
Shifting its focus to the Donbas after retreating from Kyiv in early April, Russia massed its firepower — including long-range artillery that outclassed Ukraine’s — against specific targets. It battered holdout cities from the ground and air with artillery and bombs, then sent in troops and tanks to make small advances in close combat with Ukrainian forces.
The barrages cost Ukraine dearly.
At one point in the Donbas offensive, Ukrainian officials said as many as 200 soldiers a day were dying in the fields and villages of eastern Ukraine. And Sievierodonetsk and Lysychansk are now “dead cities,” Mr. Zelensky has said, with about 90 percent of Sievierodonetsk’s buildings in ruins and its population down to 7,000 to 8,000 civilians, from 160,000 before the war.
But military analysts say Russia also suffered deep losses as the outgunned Ukrainian military held out in the twin cities, forcing Russia to dedicate more troops and weapons to the area and expend artillery shells at an extraordinarily rapid clip. Ukrainian forces have also diverted Russian resources by making small tactical gains in the last month around the cities of Kharkiv, in the east, and Kherson in the south, though Russia still maintains a significant foothold in both regions.
All that has sapped Russia’s strength in other places and may have bought Ukraine time to start deploying more powerful, longer-range weapons supplied by the West, some analysts say.
Though Western countries led by the United States have sent billions of dollars’ worth of advanced weapons to aid Ukraine, the country’s leaders have pleaded for more, and faster. Given the time needed to train Ukrainian troops in their use, it is unclear whether more arms will arrive in time to make an appreciable difference in shielding Donetsk from Russia’s advance.
For now, Ukrainians are largely reduced to hoping that Russia’s heavy losses in the Donbas will prove unsustainable, as some Western officials and analysts have predicted.
Ukrainian military officials believe the next offensive will come from the direction of Popasna, in the east toward Bakhmut, while northern and western Russian lines simply hold Ukrainian forces there in place.
Sunday also brought another reminder of the potential costs for Russia, which experienced one of its worst civilian losses of the war when explosions hit the center of a Russian city just north of Ukraine, killing four, including three Ukrainians, officials said.
Russia’s Defense Ministry blamed Ukraine for the blasts in the city of Belgorod early on Sunday. While Ukraine has occasionally hit fuel and military targets in Russia’s border region, this is the first time that Russia has accused Ukraine of targeting a major city center on the Russian side of the border in a lethal attack.
There was no immediate comment from the Ukrainian military.
In the Ukrainian struggle for national survival, the fall of Lysychansk was another bitter blow.
Dima Boyko, 16, who fled Lysychansk for Kyiv, said he last heard from his mother and grandmother, who remained in the city, two months ago, owing to the lack of cellphone service. He said he had seen videos of his own neighborhood being taken over by Russian occupiers.
“The flags have already been hung, and near my house, too — there is a Soviet monument, a tank,” he said. “From the video and photo in Telegram, you can already say that they completely occupied the city.”
Reporting was contributed by Natalia Yermak, Anton Troianovski, Austin Ramzy and Alex Traub.
