POKROVSK REGION, Ukraine -- A dire shortage of infantry troops and supply routes coming under Russian drone attacks are conspiring against Ukrainian forces in Pokrovsk, where decisive battles in the nearly three-year war are playing out — and time is running short. Ukrainian troops are losing ground around the crucial supply hub, which lies at the confluence of multiple highways leading to key cities in the eastern Donetsk region as well as an important railway station. Moscow is set on capturing as much territory as possible as the Trump administration is pushing for negotiations to end the war and recently...