The alleged crime took place on Sunday night.

Reports said that US marine Tyrone Hardnott, 38, had offered to take the girl home on his motorbike but taken her to his house instead. He then bundled her into his car on the pretext of driving her home and subsequently raped her in the vehicle.

Hardnott, who was arrested after the girl made a police report, has denied the allegations, saying he merely wanted to kiss her.

Okinawa governor Hirokazu Nakaima expressed outrage.

'It is unforgivable. I feel very angry. Every time this sort of incident happens, we ask the US forces to take drastic measures. It is regrettable that it has happened again,' he said.

Foreign Minister Masahiko Koumura sought to downplay the matter.

'We will deal with it on the basis of law and evidence. From the standpoint of public sentiment, it is not good for the US-Japan alliance. We would like to minimise the impact,' he told reporters.

Tokyo immediately requested Washington to prevent another occurrence. Similar requests to Washington in the past have, however, produced little effect.

Last year, there were 63 cases of crimes in Okinawa committed by American military personnel, a rise of six cases over the previous year.

Although Okinawa accounts for less than 1 per cent of Japanese territory, it bears the brunt of such crimes because the prefecture hosts nearly two-thirds of the 40,000 US troops stationed in Japan.

Nearly 18 per cent of the main island of Okinawa is used by the US military.

A 1995 rape of an Okinawan schoolgirl by three US troops drew huge anti-base protests, but demands by the locals for the total withdrawal of US facilities remain unmet.

To lessen the burden on Okinawans, the US has in recent years been trying to relocate some of its facilities to other parts of the country as part of a larger realignment exercise.

But the Japanese government has not been very successful so far in persuading the local authorities to accept a larger US military presence in their areas.

Okinawa governor Nakaima believed the rape incident would have little influence on ongoing discussions with the central government over the relocation of the US Futemma Air Base to another part of the prefecture.

The latest incident came just as a candidate supported by Japan's ruling coalition won a closely fought mayoral election on Sunday in the city of Iwakuni, host to a large US air base.

The focus of the election was a plan by the national government to relocate US carrier-based aircraft from a US air base south of Tokyo to the US facility in Iwakuni.

The last mayor of Iwakuni had staunchly opposed the relocation.

Newly elected mayor Yoshihiko Fukuda successfully appealed to Iwakuni voters over the benefits of receiving state subsidies to revive the flagging local economy in exchange for accepting the US military planes.

wengkin@sph.com.sg