Former Russian President Medvedev calls for preemptive strikes while Trump gives Putin a 50-day ultimatum to reach peace with Ukraine or face sanctions.

Russia now controls more than two-thirds of Ukraine’s Donetsk region — the main theater of the ground war. Russian forces have carved out a 10-mile-deep pocket around the Ukrainian troops defending the crucial city of Kostiantynivka, partly surrounding them from the east, south and west.