The attack will begin in the near future, according to Ukrainian officials. Ukraine launched the surprise offensive into Russia’s Kursk Oblast in August and is holding its positions although Russian forces have managed to reclaim around half of the territory. Russia has amassed the 50,000 troops without pulling its soldiers out of the eastern front, according to a new U.S. assessment. The east of Ukraine remains the priority for Russia and it has made notable gains in southern Donetsk Oblast, and near Toretsk, Chasiv Yar, and Kupiansk. Although managing to retake parts of Kursk Oblast with missile strikes and artillery fire, Russia has not yet launched a major assault there, a U.S. official told the New York Times. The new force comes as Russia saw its heaviest losses last month and the North Korean troops could be replacing injured and killed Russian soldiers, according to some experts.