Russian forces could be just weeks away from seizing control of the key Luhansk region in eastern Ukraine — as Ukrainian officials continued to appeal for more heavy weapons and ammunition from the West. An unnamed senior US defense official told The Washington Post that the cities of Severodonetsk and Lysychansk, which have seen some of the fiercest battles in recent weeks, could fall to Russia in the coming days. Russia has been making steady gains in the strategically important Donbas region — comprised of Luhanks and Donetsk — by pounding the area with heavy artillery day after day and...