Ukraine has lost over 40 percent of the territory in Russia’s Kursk region that it rapidly seized in a surprise incursion in August as Russian forces have mounted waves of counterassaults, a senior Ukrainian military source said.The source, who is on Ukraine’s General Staff, said Russia had deployed some 59,000 troops to the Kursk region since Kyiv’s forces swept in and advanced swiftly, catching Moscow unprepared 2-1/2 years into its full-scale invasion of Ukraine.For the latest updates on the Russia-Ukraine war, visit our dedicated page.“At most, we controlled about 1,376 square kilometers (531 square miles), now of course this territory is smaller. The enemy is increasing its counterattacks,” the source said.“Now we control approximately 800 square kilometers (309 square miles). We will hold this territory for as long as is militarily appropriate.”The Kursk offensive was the first ground invasion of Russia by a foreign power since World War Two and caught Moscow unprepared.With the