There have been occasional protests against the US military presence in Okinawa

The case had provoked fresh resentment against the heavy American military presence there.

Lance Corporal Jose W Torres, 21, had pleaded guilty to the charges of rape and assault.

He was handed over by the US military authorities to Japanese police before he was formally charged - in an apparent move by Washington to head off anger over the incident.

Under an existing agreement, the US is not obliged to hand over suspects until formal charges are laid.

A run of crimes committed by US soldiers, including the rape in 1995 of a local schoolgirl by three US servicemen, has led to some calls for the removal or scaling down of the American presence, though other residents welcome the US military's importance to the local economy.

About 26,000 of the 48,000 US military personnel in Japan are stationed on the string of islands, even though they make up less than 1% of the Japanese landmass.

Vicious attack

Corporal Torres was found guilty of raping and beating a 19-year-old woman in an attack on 25 May.

Prosecutors had demanded a five-year prison sentence, saying that Torres had punched the woman in the face and broken her nose before raping her on a road near the town of Kin.

The judge called the circumstances of the crime "vicious", the French agency AFP reported.

"The feelings of the family and victim in demanding a severe punishment are natural, and I cannot ignore the anxiety caused to the neighbours and general citizens," Judge Nobuyuki Yokota said.