MOSCOW—Close to 200,000 Russian troops have been killed or wounded in the war in Ukraine, according to estimates from U.S. and European officials, a toll that is likely to continue to rise as the Kremlin readies a fresh offensive in the coming weeks. The U.S. military, which keeps rough estimates on Russian casualties in Ukraine, puts the figure for wounded and dead at roughly 180,000, though officials stressed such figures aren’t precise, a U.S. defense official said. The tally matched assessments by Norway’s defense chief Gen. Eirik Kristoffersen, who said last week that the number of Russian soldiers killed or...