Ukrainian troops on Sunday successfully pressed their swift counteroffensive in the northeastern part of the country, even as a nuclear power plant in the Russia-occupied south completely shut down in a bid to prevent a radiation disaster as fighting raged nearby.
Kyiv's action to reclaim Russia-occupied areas in the Kharkiv region forced Moscow to withdraw its troops to prevent them from being surrounded, leaving behind significant numbers of weapons and munitions in a hasty retreat as the war marked its 200th day on Sunday.
A jubilant Ukrainian President Volodymyr Zelenskyy mocked the Russians in a video address Saturday night, saying that "the Russian army in these days is demonstrating the best that it can do — showing its back."
He posted a video of Ukrainian soldiers hoisting the national flag over Chkalovske, another town reclaimed in the counteroffensive.
While most attention was focused on the counteroffensive, Ukraine's nuclear energy operator said the Zaporizhzhia nuclear power plant, Europe's largest, was reconnected to Ukraine's electricity grid, allowing engineers to shut down its last operational reactor to safeguard the plant amid the fighting.
The plant, one of the 10 biggest atomic power stations in the world, has been occupied by Russian forces since the early days of the war. Ukraine and Russia have traded blame for shelling around it.
Since a Sept. 5 fire caused by shelling knocked the plant off transmission lines, the reactor was powering crucial safety equipment in so-called "island mode" — an unreliable regime that left the plant increasingly vulnerable to a potential nuclear accident.
Russian President Vladimir Putin discussed the situation at the plant in a call Sunday with French President Emmanuel Macron, the Kremlin said.
Ukraine's military chief, Gen. Valerii Zaluzhnyy, announced that its forces had recaptured about 160 square miles since the counteroffensive began in early September. He noted that Ukrainian troops are only about 30 miles from the border with Russia.
Kharkiv Gov. Oleh Syniehubov said Ukrainian troops have reclaimed control of more than 40 settlements in the Kharkiv region, noting he couldn't give a precise number because the operation is still unfolding.
Defense Minister Anna Malyar said Ukrainian forces are firing shells containing propaganda into areas where they seek to advance.
"One of the ways of informational work with the enemy in areas where there is no Internet is launching propaganda shells," she wrote on Facebook. "Before moving forward, our defenders say hello to the Russian invaders and give them the last opportunity to surrender. Otherwise, only death awaits them on Ukrainian soil."
The Russian pullback marked the biggest battlefield success for Ukrainian forces since they thwarted a Russian attempt to seize the capital, Kyiv, at the start of the nearly seven-month war. The Kharkiv campaign came as a surprise for Moscow, which had relocated many of its troops from the region to the south in expectation of a counteroffensive there.
In an awkward attempt to save face, the Russian Defense Ministry said Saturday the troops' withdrawal from Izyum and other areas was intended to strengthen Moscow's forces in the neighboring Donetsk region to the south.
The explanation sounded similar to the justification Russia gave for pulling back from the Kyiv region earlier this year when they failed to take the capital.
The Russian forces around Izyum have been key for Moscow's effort to capture the Donetsk region, and their pullback will dramatically weaken its capability to press its offensive on Ukrainian strongholds of Sloviansk and Kramatorsk to the south.
A map released by the Russian Defense Ministry on Sunday showed its forces retreating to a narrow patch of land along the border.
Igor Strelkov, who led Russia-backed forces when the separatist conflict in the Donbas erupted in 2014, mocked the Russian Defense Ministry's explanation of the retreat, suggesting that handing over Russia's own territory near the border was a "contribution to a Ukrainian settlement."
The retreat drew an angry response from Russian military bloggers and nationalist commentators, who bemoaned it as a major defeat and urged the Kremlin to step up its war efforts. Many scathingly criticized Russian authorities for continuing with fireworks and other lavish festivities in Moscow that marked a city holiday on Saturday despite the debacle in Ukraine.
Just as the Russian forces were hastily pulling back from Izyum under Ukrainian fire on Saturday, Putin attended the opening of a huge Ferris wheel at a Moscow park, although it reportedly closed for repairs soon thereafter. He also inaugurated a new transport link and a sports arena.
The action underlined the Kremlin's narrative that the war it calls a "special military operation" was going according to plan without affecting Russians' everyday lives.
Pro-Kremlin political analyst Sergei Markov criticized the Moscow festivities as a grave mistake.
"The fireworks in Moscow on a tragic day of Russia's military defeat will have extremely serious political consequences," Markov wrote on his messaging app channel. "Authorities mustn't celebrate when people are mourning."
In a sign of a potential rift in the Russian leadership, Ramzan Kadyrov, the Kremlin-backed head of Chechnya, said the retreat resulted from blunders by the Russian military leadership.
"They have made mistakes and I think they will draw the necessary conclusions," Kadyrov said. "If they don't make changes in the strategy of conducting the special military operation in the next day or two, I will be forced to contact the leadership of the Defense Ministry and the leadership of the country to explain the real situation on the ground."
Despite Ukraine's gains, U.S. Secretary of State Antony Blinken and the head of NATO warned Friday the war would likely drag on for months. Blinken said the conflict was entering a critical period and urged the West to keep supporting Ukraine through what could be a difficult winter.
The U.S. and its NATO allies have been working to make sure that Ukrainian forces have "the things that they most need right on the moment," said Sen. Tim Kaine, a Virginia Democrat on the Senate Foreign Relations Committee.
"And we are seeing the Ukrainians with a tremendous patriotic resolve -- but also after eight years of joint training with the U.S. military, going back to 2014 with the Crimea invasion -- we're seeing the combined effect of collaborative training and resources that are right on time right at the moment, showing that Vladimir Putin's grandiose dissolutions about what he might do in Ukraine are hollow and they're failing," he told CNN.
Additional reporting by the Associated Press.