NATO Chief: Russia-Ukraine War Could Last for YearsRussia’s war against Ukraine could last for years, NATO Secretary-General Jens Stoltenberg warned Sunday, but he said Western allies should not curb their support for Kyiv’s forces. "We must prepare for the fact that it could take years,” Stoltenberg told the German weekly Bild am Sonntag. “We must not let up in supporting Ukraine, even if the costs are high, not only for military support, also because of rising energy and food prices." British Prime Minister Boris Johnson, who visited Kyiv on Friday with an offer of training for Ukrainian forces, also warned against the risk of "Ukraine fatigue" as the war grinds on toward the four-month mark in the coming days. In an opinion piece in London's Sunday Times, Johnson said this meant ensuring "Ukraine receives weapons, equipment, ammunition and training more rapidly than the invader." Ukrainian President Volodymyr Zelenskyy, who has rallied his countrymen with daily videos, said he had visited forces in the southern Mykolaiv region, about 550 kilometers south of Kyiv. "Their mood is assured: They all do not doubt our victory," he said in a video Sunday that appeared to have been recorded on a moving train. "We will not give the south to anyone, and all that is ours we will take back" from the Russians. Zelenskyy said Russian forces had destroyed parts of the Mykolaiv and Odesa regions. "The losses are significant,” he said. “Many houses have been destroyed; civilian logistics have been disrupted.” While Russia failed early in the war to topple Zelenskyy’s government and capture Kyiv, intense fighting rages in the eastern part of the country, centering on the embattled industrial city of Sievierodonetsk in Luhansk province, which is part of the broader Donbas region that Russia is trying to control. Shelling continues, but Luhansk Governor Serhiy Haidai told Ukraine television, "All Russian claims that they control the town are a lie. They control the main part of the town, but not the whole town." But he said the battles made evacuations from the city impossible. Haidai said that in Sievierodonetsk's twin city of Lysychansk, residential buildings and private houses had been destroyed. "People are dying on the streets and in bomb shelters," he said. Russia's defense ministry said its forces have taken control of Metolkine, just southeast of Sievierodonetsk, with Russian state news agency Tass claiming that many Ukrainian fighters had surrendered there. Ukraine's military acknowledged that Russia had "partial success" in the area. Analysts at a Washington-based think tank, the Institute for the Study of War, said in a note that "Russian forces will likely be able to seize Sievierodonetsk in the coming weeks, but at the cost of concentrating most of their available forces in this small area.” British defense officials, assessing the intense fighting in the Donbas region, said morale among troops on both sides was likely diminishing. "Combat units from both sides are committed to intense combat in the Donbas and are likely experiencing variable morale," Britain's defense ministry said in its daily assessment. "Ukrainian forces have likely suffered desertions in recent weeks," the assessment said, but added that "Russian morale highly likely remains especially troubled." It said, “Cases of whole Russian units refusing orders and armed standoffs between officers and their troops continue to occur." Some information from this report came from The Associated Press and Reuters.