KYIV, Ukraine — Ukrainian officials said they require coordinates provided or confirmed by the United States and its allies for the vast majority of strikes using its advanced U.S.-provided rocket systems, a previously undisclosed practice that reveals a deeper and more operationally active role for the Pentagon in the war. The disclosure, confirmed by three senior Ukrainian officials and a senior U.S. official, comes after months of Kyiv’s forces pounding Russian targets — including headquarters, ammunition depots and barracks — on Ukrainian soil with the U.S.-provided High Mobility Artillery Rocket System, or HIMARS, and other similar precision-guided weapons such as...