Ukraine Routs Russian Forces in Northeast, Forcing a Retreat

KHARKIV, Ukraine — Stunned by a lightning advance by Ukrainian forces that cost it over 1,000 square miles of land and a key military hub, Russia on Sunday acknowledged that it had lost nearly all of the northern region of Kharkiv after a blitzkrieg thrust that cast doubt on a premise — widely held in Moscow and parts of the West — that Ukraine could never defeat Russia.

Russia’s pell-mell retreat from a wide section of Ukrainian territory it seized in the early summer rattled Kremlin cheerleaders and amplified voices in the West demanding that more weapons be sent to Ukraine so that it could win.

Victory for Ukraine is still far from certain, particularly with a second Ukrainian offensive in the south making far less rapid progress. Russian forces are dug into strong defensive positions near the Black Sea port city of Kherson, forcing Ukrainian troops to pay heavily for every foot of territory they retake.

But the speed of Ukraine’s advances over the weekend in the northeast — an area used by Russia as a stronghold — has muted the gung-ho bluster of Kremlin cheerleaders. It has also undermined arguments in places like Germany that providing more and better arms to Ukraine would only lead to a long and bloody stalemate against a Russian military destined to win.

Late Sunday, in a strike that Ukrainian officials condemned as a fit of pique over its losses, Moscow attacked infrastructure facilities in Kharkiv, leaving many civilians without power and water. President Volodymyr Zelensky said there was a “total blackout” in the regions of Kharkiv and Donetsk.

“No military facilities,” he wrote on Twitter. “The goal is to deprive people of light and heat.”

Russia’s retreat in the northeast is the biggest embarrassment for President Vladimir V. Putin’s larger and better equipped forces since their attempt to seize Kyiv, the Ukrainian capital, was repelled at the start of the invasion. Amid heavy casualties, logistical problems and declining morale in Russia’s military, its performance has prompted discontent among pro-Kremlin bloggers and staunch Putin loyalists, creating new challenges for the Russian leader.

Among them is the collapse of a widespread assumption, both inside and outside Russia, that Russia would inevitably triumph in the end. On Sunday, Ukraine’s defense ministry claimed that its forces had advanced to a checkpoint near the Russian border in northeastern Ukraine, Hoptivka, an assertion that could not be independently confirmed.

Ukrainian allies rejoiced at Russia’s battlefield setbacks.

“Let me be frank,” said Gabrielius Landsbergis, the foreign minister of Lithuania, one of Ukraine’s most steadfast supporters. “It is now beyond doubt that Ukraine could have thrown Russia out months ago if they had been provided with the necessary equipment from Day 1.”

Speaking at a news conference with his German counterpart, Ukraine’s foreign minister, Dmytro Kuleba, said, “And so I reiterate: The more weapons we receive, the faster we will win, and the faster this war will end.”

Ukraine’s rapid gains followed increased intelligence sharing with the United States, American officials said. Over the summer, as they planned their counteroffensive in the northeast, Ukrainian officials began to offer more real-time intelligence to their American counterparts, a shift that allowed the United States to provide better and more relevant information about Russian weaknesses, officials said.

American officials welcomed Ukraine’s rapid advance as a heartening development. But senior Pentagon and White House officials urged caution, voicing doubts about the capacity of Ukrainian forces to push Russia back to the lines that existed on Feb. 23, the day before the invasion. Still, they said that the progress suggested the Russian forces were in significant disarray.

For months now, administration officials have said there is no hope of a diplomatic solution to the war unless Mr. Zelensky’s forces win back enough territory to have the upper hand in any negotiated cease-fire or armistice. But the fear is that if Mr. Putin believes he is losing the war, he may deploy unconventional weapons.

Military analysts are debating whether Ukraine’s successes in the north were the result of an ingenious ruse aimed at diverting Russia’s strength toward the south. A Ukrainian counteroffensive there that was telegraphed for weeks may have been partly a feint, they say.

In a sign of the shock, and even despair, spreading through the ranks of the war’s most vocal supporters in Russia, Ramzan Kadyrov, the strongman leader of Chechnya and a staunch Putin loyalist, criticized the Russian Army’s leadership on Sunday and expressed dismay over its performance in northeastern Ukraine.

Russia’s ministry of defense had “made mistakes,” he said in a post on social media, and the military and national leadership needed to explain “the real situation on the ground.”

But far from acknowledging the setbacks, the official journal of the Russian government, Rossiskaya Gazeta, headlined its main war report on Sunday with an account of how the “Kyiv regime” had suffered heavy casualties. It claimed that more than 4,000 Ukrainian soldiers had been killed from Tuesday to Saturday.

And the authorities in Moscow presented the rout in the northeast as a planned “regrouping.”

The Institute for the Study of War, a research group in Washington, gave a starkly different assessment. In a report, it said that Russia’s northern front was “collapsing” and dismissed claims by Moscow that its troops had simply been ordered to “regroup.”

Russian forces, the institute said, “are not conducting a controlled withdrawal and are hurriedly fleeing.”

In Kyiv, the mood was euphoric.

“We’ve been waiting for this for a long time,” said Rumil Khabibulin, an actor. “My wife, my children, me — all of our spirits are lifted. I think it’s a big turning point in the war, and Russia will fall apart.”

With nearly all news outlets in Russia in the grip of the Kremlin, however, there was little sign of eroding public support for Mr. Putin or for the war that the Kremlin insists on describing as a “special military operation.”

Schooled from childhood about how the armies of Napoleon and then Hitler won battles all the way to Moscow only to be crushed in the end, many Russians are programmed to believe official claims that their country, no matter what the setbacks of the moment, is marching to eventual victory.

Few people have much knowledge of Russia’s catastrophic 1904-5 war with Japan, which, like the invasion of Ukraine, was driven by imperial hubris and contempt for an enemy that Czar Nicholas II expected to crumble in a “short, victorious war.” Russia lost much of its navy and suffered total defeat at the hands of Japan, a humiliation that helped fuel Russia’s 1905 revolution.

For the moment, the Kremlin is sticking to breezy denials of defeats and business-as-usual insouciance by Mr. Putin, who, as Russian lines buckled on Saturday in the Kharkiv region, inaugurated a giant Ferris wheel in a Moscow park. Reports from social media said the wheel quickly broke down, leaving riders stranded in the air.

After presiding over festive fireworks on Saturday celebrating the 875th anniversary of Moscow’s founding, Mr. Putin turned his attention back to his war in Ukraine on Sunday, when, according to a Kremlin statement, he spoke by phone with President Emmanuel Macron of France, their first conversation since Aug. 19.

While insisting that it had inflicted serious damage on Ukrainian forces, the defense ministry in Moscow obliquely acknowledged that the war was not going according to plan. It released a map on Sunday that indicated Russian troops had been driven from nearly all of the Kharkiv region and now controlled only a sliver of land on its eastern edge along the Oskil River.

One Russian military blogger, Yuri Podolyaka, reported that Russian forces had been ordered to evacuate the entire region. No such order has been confirmed, but Russian forces, thrown into disarray by the pace of Ukraine’s advance, are clearly now focused on preventing losses in the adjacent regions of Luhansk and Donetsk.

Other Russian military bloggers, who generally cheer the war effort but also offer a less varnished take on reality on the ground than state media outlets, reported that Ukraine was now attacking the small city of Lyman, seized by Russia in May, and that Russian forces there were in need of reinforcements.

Lyman’s mayor, Oleksandr Zhuravlev, told the Ukrainian news media that as of Saturday night, the fight was still underway. “The Russian military is still resisting,” he said. “Our flag is not there yet.”

The capture of Lyman would be another serious reversal of fortunes for Russia, whose seizure of the city in early summer presaged what at the time seemed like an inexorable and irreversible Russian campaign to conquer the area, including the bigger nearby towns of Sievierodonetsk and Lysychansk.

On Sunday, Mr. Zelensky claimed that Ukrainian forces had recaptured Chkalovske, a village in the Kharkiv region that lies roughly halfway between Izium, an important Russian military hub seized back by Ukraine on Saturday, and Ukraine’s second-largest city, Kharkiv, which has been struck repeatedly by Russian forces.

Suggesting the blitz still has room to run, Serhiy Grabskyi, a former Ukrainian army colonel and commentator on the war for Ukrainian news media, said that when troops fell back in disarray, as Russians were now doing, they tend to unnerve the soldiers they encounter as they fled. “They will spread demoralization to other troops,” he said.

But reaching too far could leave the Ukrainian Army stretched thin and vulnerable, Mr. Grabskyi warned. “Now — and it’s painful for me to say as a Ukrainian — we have to decide where to stop,” he said.

Andrew E. Kramer reported from Kharkiv, and Andrew Higgins from Warsaw. Reporting was contributed by Thomas Gibbons-Neff and Jeffrey Gettleman from Kyiv; Maria Varenikova from Kharkiv; Ivan Nechepurenko from Tbilisi, Georgia; and David E. Sanger from Washington.