The prefectural administration of Okinawa said the curfew would be imposed as most crimes committed by US servicemen tended to take place after midnight.

"We hope that it will help prevent the recurrence of crimes," Tadanobu Higa, director of military base affairs for the Okinawa prefectural government, told AFP by telephone.

"Educational programs by the US forces in the past have failed to produce results. The number of crimes is still on the increase," he added.

Offences committed by servicemen have fueled strong protests among islanders against the concentration of US troops on the Okinawan chain, particulary after the 1995 gang-rape of a 12-year-old local girl by three US servicemen.

Okinawa, located within the striking distance of China and the Korean peninsula hosts roughly two-thirds of the 47,000 US troops in Japan. It remained under post-World War II US military occupation until 1972.

US marines with the rank of sergeant or lower stationed in Japan will be barred from going off base from midnight to 5 am in an indefinite curfew beginning on June 11, the US military daily Stars and Stripes reported.

But non-commissioned officers, who have demonstrated "integrity, maturity, reliability and exceptional performance" may be exempted from the ban, it added.

It is the first time for a curfew to be imposed on US service personnel in Okinawa, since the Group-of-Eight (G8) summit held there in 2000 amid airtight security.

Lieutenant General Robert Blackman, commander of US Marine Corps in Japan, told the GI daily that the curfew was in response to crimes involving US service members in Japan, which have been on the rise since 1998.

"This is not a form of punishment," Blackman was quoted as saying. "Its a way of controlling where liberty is conducted during those peak times.

"These incidents have a negative effect on our relationship here and I want to turn it around; I want to push that curve in the other direction," he told the paper.

According to the Okinawan prefectural government, 112 US service members were arrested in 2003, including 48 held on suspicion of theft.

The annual total has steadily increased since 1998 from a steady total of 40 in the previous three years, during which antipathy toward US troops remained fierce after the gang rape.

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