TOKYO: Two US servicemen were arrested on suspicion of raping a Japanese woman in Okinawa, reports said, as anti-American feeling runs high on the strategically vital island.

The incident comes amid swelling protests over the recent deployment on the island of 12 Osprey transport aircraft, with the plane’s perceived poor safety sparking concern among local residents.

National broadcaster NHK said that the two, both aged 23, were arrested for the alleged assault before dawn on Tuesday.

One of the sailors admitted the attack but the other has denied it, according to TV Asahi. A spokesman for the Okinawa prefectural police refused to comment on the reports.

US Ambassador John Roos on Wednesday moved swiftly to reassure people of Okinawa that he shared their anger over an incident that has the potential to act as a lightning rod for growing anti-US feeling.

He said that the US government and military would “provide full, complete and unequivocal cooperation to the Japanese authorities in their investigation.”

After a meeting with vice foreign minister Shuji Kira, who is standing in while Foreign Minister Koichiro Gemba is in Europe, Roos said: “I do understand the anger that many people feel with respect to this reported incident.”

Okinawa governor Hirokazu Nakaima, a vocal critic of the size of the vast US presence on the island, met Defense Minister Satoshi Morimoto and expressed his fury, describing the alleged crime as “insane.”

“We cannot accept this no matter how much [the US military presence] is claimed to be necessary for national security,” he said.

Prime Minister Yoshihiko Noda also chimed in, saying that the alleged crime was “intolerable.”

The incident has the potential to snowball, feeding in to the increasingly vociferous anti-base movement. Previous attacks have generated huge outpourings of anger.

The gang rape of a 12-year-old Okinawan girl by US servicemen in 1995 sparked mass protests resulting in a US-Japan agreement to reduce the huge US military presence on the Okinawan chain.

But the agreement has been bogged down for years over plans to relocate the Futenma US Marine airbase, which currently sits in a crowded urban area, to a coastal zone.

Islanders want to see the airbase moved off the island chain and insist the rest of Japan should shoulder more of the burden of the US presence.

Okinawa is a reluctant host to about half of the 47,000 US military personnel stationed in Japan.

In September tens of thousands of people rallied against deployment of the tilt-rotor Osprey, which can take off and land like a helicopter and fly like a plane.

A number of crashes involving the aircraft sparked safety fears, but commentators say the Osprey is a proxy issue for a people who are fed up of the huge US presence.

Washington sees the island as a vital strategic base in a region that is increasingly seeing the power of China’s rising military.