The United States took control of the island in the 1898 Spanish-American War, as part of the Treaty of Paris. Guam came to serve as a station for American ships traveling to and from the Philippines, while the Northern Mariana Islands passed to Germany, and then to Japan.
During World War II, Guam was attacked and invaded by the armed forces of Japan on December 8, 1941. Anticipating the attack, the Navy had all military dependents transported away from the island, but did not inform the native Chamorros of the possible bombardment.[citation needed]
The Northern Mariana Islands had become a Japanese protectorate before the war. It was the Chamorros from the Northern Marianas who were brought to Guam to serve as interpreters and in other capacities for the occupying Japanese force. The Guamanian Chamorros were treated as an occupied enemy by the Japanese military. After the war, this would cause resentment between the Guamanian Chamorros and the Chamorros of the Northern Marianas. Guam's Chamorros believed their northern brethren should have been compassionate towards them, whereas having been occupied for over 30 years, the Northern Mariana Chamorros were loyal to Japan.
Guam's Japanese occupation lasted for approximately thirty-one months. During this period, the indigenous people of Guam were subjected to forced labor, family separation, incarceration, execution, concentration camps and forced prostitution. Approximately one thousand people died during the occupation, according to Congressional Testimony in 2004. Some historians estimate that war violence killed 10% of Guam's some 20,000 population.[10]
The United States returned and fought the Battle of Guam on July 21, 1944, to recapture the island from Japanese military occupation. More than 18,000 Japanese were killed as only 485 surrendered. Sergeant Shoichi Yokoi, who surrendered in January 1972, appears to have been the last confirmed Japanese holdout in Guam.[11] To this day, Guam remains the only U.S. soil with a sizable population to have been occupied by a foreign military power, since the War of 1812. The United States also captured and occupied the Northern Marianas.