On July 17, 1944, napalm bombs were dropped for the first time by American P-38 pilots on a fuel storehouse at Coutances, near St. Lô, France. Napalm bombs were first used in the Pacific Theatre during the Battle of Tinian by Marine pilots. Its use was made difficult by problems with mixing, fusing and the release mechanisms. In World War II, Allied forces bombed cities in Japan with napalm, and used it in bombs and flamethrowers in Germany and the Japanese-held islands. It was used by the Greek army against communist guerrilla fighters during the Greek Civil War, by United Nations forces in Korea, by Mexico in the late 1960s against guerrilla fighters in Guerrero and by the United States during the Vietnam War.