TOKYO: Japan lodged a protest on Thursday (MAy 19) with the United States after a US base worker was arrested in connection to the suspicious death of an Okinawa woman, media reported, a week before President Barack Obama pays a high-profile visit to the country.

Okinawa was the site of brutal fighting in World War II but is now considered a strategic linchpin supporting the two countries' decades-long security alliance.

More than half of the 47,000 US military personnel in Japan are stationed on Okinawa, and crimes by service personnel - including rapes - have sparked angry local protests in the past.

Foreign Minister Fumio Kishida summoned US ambassador Caroline Kennedy to the foreign ministry in Tokyo shortly after Okinawa police arrested a 32-year-old civilian US base worker in connection with the death of a 20-year-old Okinawa woman.

"It is extremely regrettable that the very cruel and atrocious case occurred," Kishida told Kennedy, according to Nippon Television Network.

Police arrested Kenneth Franklin Shinzato, a former US Marine who lives in southern Okinawa and works at the US Air Force's Kadena Air Base, for allegedly disposing of the woman's body.

Local media said police suspect Shinzato murdered the victim, identified as Rina Shimabukuro, who had been missing since late April.

We "extend our deepest sympathies to the people of Japan, and express our gratitude for the trust that they place in our bilateral alliance and the American people," Pentagon spokesman Peter Cook said, vowing to assist the investigation "in any way that we can."

US State Department spokesman John Kirby called the case a tragedy that was "obviously an outrage."

Shimabukuro's body was found in a weed-covered area in southern Okinawa after investigators conducted a search based on the suspect's deposition, while police found DNA matching the dead woman's in the man's car, Kyodo news agency said.

In 1995 the abduction and rape of a 12-year-old girl on Okinawa by three US servicemen sparked massive protests, prompting Washington to pledge efforts to strengthen troop discipline to prevent such crimes and reduce the US footprint on the island.

But continued crimes by American personnel remain an irritant - a potent rallying point for Okinawans and others in Japan who oppose the presence of the bases on the crowded island, where pacifist sentiment runs high.

The arrest came ahead of Obama's trip to Japan next week to attend a Group of Seven summit and to make a landmark visit to Hiroshima in his final year in office.

Obama will become the first sitting US president to visit Hiroshima, where the first atomic bomb was dropped on August 6, 1945, killing an estimated 140,000 people, either directly or from the bombing's after-effects.