U.S. Forces Japan said the Naval Criminal Investigative Service (NCIS) was working with local police to look into the deaths of a Navy sailor assigned to a Marine unit and an Okinawa resident. "This is an absolute tragedy and we are fully committed to supporting the investigation," it said in a statement, according to the reporting on the crime from The Associated Press.
AP said Vice Minister of Foreign Affairs Takeo Akiba telephoned U.S. Ambassador William Hagerty, asking for cooperation with both the inquiry and efforts to prevent a recurrence.
Although Okinawa makes up less than 1 percent of Japan's land space, AP said, it hosts about half of the 54,000 American troops stationed in Japan, and is home to 64 percent of the land used by U.S. bases in the country.
People there have long complained about crime, noise and the destruction of the environment as a consequence of the military presence.
A plan to relocate a Marine Corps air station called Futenma to a less populated part of Okinawa has also been contentious, AP said, and Denny Tamaki, Okinawa's governor, is pushing to have the base moved off the island altogether.
The Associated Press contributed to this report.