Ukraine retakes swathes of territory from Russian forces as war enters 200th day Firefighters battle a blaze after a Russian rocket attack hit an electric power station in Ukraine's northeastern Kharkiv region on Sunday. (Kostiantyn Liberov/The Associated Press) Ukrainian troops on Sunday successfully pressed their swift counter-offensive 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 "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. Meanwhile, Ukraine's military chief, Gen. Valerii Zaluzhnyy, said its forces had recaptured about 3,000 square kilometres since the counter-offensive began in early September. He said Ukrainian troops are only 50 kilometres from the border with Russia. Kharkiv Gov. Oleh Syniehubov said Ukrainian troops have reclaimed control of more than 40 settlements in the region, noting he couldn't give a precise number because the operation is still unfolding. Defence 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 Ukrainian General Staff said Russian forces had also left several settlements in the Kherson region as Ukrainian forces pressed the counter-offensive. It did not identify the towns. An official with the Russian-backed administration in the city of Kherson, Kirill Stremousov, said on social media that the city was safe and asked everyone to stay calm. Ukrainian troops walk past a former position of the Russian soldiers, captured during a counter-offensive operation, Ukraine's northeastern Kharkiv region on Sunday. (Press service of the Commander-in-Chief of the Armed Forces of Ukraine/Reuters) The Russian pullback marked the biggest battlefield success for Ukrainian forces since they thwarted a Russian attempt to seize the capital, Kyiv, near the start of the 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 counter-offensive there. In an awkward attempt to save face, the Russian Defence Ministry said Saturday the troops' withdrawal from Izyum and other areas was intended to strengthen Moscow's forces in the neighbouring Donetsk region to the south. The explanation sounded similar how Russia justified its pulling back from Kyiv earlier this year. Igor Strelkov, who led Russia-backed forces when the separatist conflict in the Donbas erupted in 2014, mocked the Russian Defence Ministry's explanation of the retreat, suggesting that handing over Russia's own territory near the border was a "contribution to a Ukrainian settlement." A residential building destroyed by a strike is seen in Ukraine's central Mykolaiv region on Sunday. (Umit Bektas/Reuters) 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, urging the West to keep supporting Ukraine through what could be a difficult winter. Sen. Tim Kaine, a Virginia Democrat and member of the Senate Foreign Relations Committee, called Ukrainian advances very encouraging. "I'm proud that the U.S. and our allies have locked arms to support the Ukrainian people in this fight," Kaine said in a statement to The Associated Press. "We and our allies must keep standing with Ukraine. Putin needs to recognize that the only way out is to end his failed war." Nuclear plant still in peril While most attention was focused on the counter-offensive, 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. WATCH | UN presses for safety zone at nuclear power plant: UN presses for safety zone around Ukraine's Zaporizhzhia nuclear plant The UN's International Atomic Energy Agency has urged Russia and Ukraine to establish a 'nuclear safety and security protection zone' around the Zaporizhzhia power plant. The International Atomic Energy Agency, the UN nuclear watchdog that has two experts at the plant, welcomed the restoration of external power. But the agency's directorgeneral, Rafael Grossi, said he remains "gravely concerned about the situation at the plant, which remains in danger as long as any shelling continues." He said talks have begun on establishing a safety and security zone around the plant. In a call Sunday with Russian President Vladimir Putin, French President Emmanuel Macron urged the withdrawal of Russian troops and weaponry from the plant in line with IAEA recommendations.