The United States Fifth Army was one of the principal formations of the U.S. Army in the Mediterranean during World War II, and was the first American field army ever to be activated outside of the United States. It was officially activated on 5 January 1943 at Oujda, French Morocco and made responsible for the defence of Algeria and Morocco. It was also given the responsibility for planning the American part of the invasion of mainland Italy, and therefore was not involved in the Allied invasion of Sicily (codenamed Operation Husky), where it was instead assigned the role of training combat troops destined for Sicily. The United States Fifth Army was initially commanded by Lieutenant General Mark Wayne Clark, who would lead the Fifth Army for nearly two years, and was to experience some of the toughest fighting of World War II, where it was engaged on the Italian Front, which was, in many ways, often more reminiscent of the trench warfare of the Western Front in World War I. Writing to Lieutenant General Jacob L. Devers (American deputy to Field Marshal Sir Henry Maitland Wilson, Mediterranean Theater commander) in late March 1944, Clark explained the difficulties of the fighting in Italy so far, which could be said of the whole campaign. They were, he claimed, "Terrain, weather, carefully prepared defensive positions in the mountains, determined and well-trained enemy troops, grossly inadequate means at our disposal while on the offensive, with approximately equal forces to the defender."