YAVORIV, Ukraine (Reuters) – Ukrainian troops on Friday trained at the Yavoriv military base in western Ukraine, using anti-tank missiles, launchers and other military hardware delivered by the United States as part of a $200 million security package. Soldiers, some in white camouflage gear, fired missiles or stood observing, while military vehicles drove across a snowy landscape. Ukraine has received planeloads of U.S. military aid as it braces for a possible attack after Russia massed tens of thousands of troops near Ukraine’s borders in recent weeks. Moscow denies planning any such offensiv…