TOKYO (Reuters) - An American man working at a U.S. military base in Japan was arrested on Thursday on suspicion of dumping the body of a 20-year-old Japanese woman, police said, in a case likely to stir anti-U.S. sentiment ahead of a visit by President Barack Obama.
The 32-year-old civilian working at the base on the island of Okinawa admitted to abandoning the corpse but did not make any comments about whether he killed the woman, an Okinawa police spokesman said.
Japan's Foreign Minister Fumio Kishida summoned Caroline Kennedy, U.S. ambassador to Japan, to lodge a protest.
"I expressed a strong regret to Ambassador Kennedy and lodged a stern protest. I told her an incident like this is inexcusable and that I feel strong indignation," Kishida told reporters after the meeting.
Kennedy told Kishida the United States would redouble its efforts to prevent the recurrence of similar incidents, the foreign minister said.
In Washington, the Pentagon said the individual was a contractor, without naming the person.
"I want to assure you that the Secretary and the Department of Defense (are) determined to provide complete cooperation to the government of Japan and local authorities regarding this investigation," Pentagon spokesman Peter Cook said during a briefing.
State Department spokesman John Kirby expressed condolences and said U.S. authorities were following the case closely.
"This is a terrible tragedy and it's obviously an outrage. We're treating this situation with the utmost seriousness," Kirby said at a daily news briefing.
Obama, who is due to attend a Group of Seven summit next week, will become the first U.S. president to visit the city of Hiroshima, destroyed by a U.S. atomic bomb 71 years ago.
Earlier this year, a U.S. sailor was arrested on suspicion of raping a woman at a hotel in Naha in the south of Okinawa.
Okinawa, the site of a bloody World War Two land battle, hosts the bulk of U.S. military forces in Japan, and many residents resent what they see as an unfair burden. U.S. installations take up about 18 percent of Okinawa's land.
In 1995, a 12-year-old Japanese schoolgirl was raped by three U.S. servicemen on Okinawa, sparking huge protests among local residents, many of whom associate U.S. bases with noise, pollution and crime.
(Reporting by Kiyoshi Takenaka; additional reporting by Doina Chiacu and Idrees Ali in Washington; Editing by Ed Osmond and Andrew Hay)