The Allies invaded French North Africa in November 1942, securing the surrender of Vichy French forces within days of landing. At the January 1943 Casablanca Conference, the Allies agreed to defeat Axis forces in North Africa and then launch an invasion of Sicily, with an attack on France to take place in 1944. At the conference, Roosevelt also announced that he would only accept the unconditional surrender of Germany, Japan, and Italy. In February 1943, the Soviet Union won a major victory at the Battle of Stalingrad, and in May 1943, the Allies secured the surrender of over 250,000 German and Italian soldiers in North Africa, ending the North African Campaign. The Allies launched an invasion of Sicily in July 1943, capturing the island by the end of the following month. In September 1943, the Allies secured an armistice from Italian Prime Minister Pietro Badoglio, but Germany quickly restored Mussolini to power. The Allied invasion of mainland Italy commenced in September 1943, but the Italian Campaign continued until 1945 as German and Italian troops resisted the Allied advance.