On June 3/4, 1942, the Japanese Navy attacked the Territory of Alaska as part of the Aleutian Islands Campaign with the bombing of Dutch Harbor in the city of Unalaska, inflicting destruction and killing 43 Americans. A few days later, 6,000–7,000 Japanese troops landed and occupied the Aleutian Islands of Attu and Kiska; they were driven out entirely a year later between May and August 1943 by U.S. and Canadian forces. The Aleutian Islands campaign in early June 1942 was the only foreign invasion of U.S. soil during World War II and the first significant foreign occupation of American soil since the War of 1812. Japan also conducted air attacks through the use of fire balloons. Six American civilians were killed in such attacks; Japan also launched two manned air attacks on Oregon as well as two incidents of Japanese submarines shelling the U.S. West Coast.