Moscow’s victory in Kursk would deprive Kyiv of key leverage in U.S.-brokered efforts to negotiate an end to the more than 3-year-old war.

Russia and Ukraine dispute the status of the Kursk region, which Kyiv invaded last year in a surprise and successful incursion into Russian territory.

The Russian military announced today that all Ukrainian troops have been forced out of Russia's Kursk region, marking a ...