Ukrainian armed forces commander General Valeriy Zaluzhnyi, who was replaced on Thursday, became a national hero for repelling Moscow's invading forces two years ago but suffered battlefield setbacks as the war ground on. The move ends intense speculation over his fate after reported frictions between him and President Volodymyr Zelenskiy, whose authority will be tested as he seeks to rally troops under a new army chief and change the dynamic of the war. Ukrainian forces are struggling after a counteroffensive launched last June made little headway in the south and east, while Russian forces are inflicting small but costly defeats at several points along the 1,000-km (620-mile)front.