He then took the 40-year-old victim back to his room where he raped her

A U.S. Navy sailor was sentenced Friday to two-and-a-half years hard labor for raping a Japanese tourist in Okinawa.

Justin Castellanos, 24, who was based in the district's Camp Schwab, pleaded guilty in May to raping the 40-year-old victim in his hotel room in Naha, south Japan on March 13.

The serviceman had found the woman, who was drunk and asleep in the hotel lobby, and taken her up to his room where he assaulted her.

'I am sorry for what I have done,' he told the court. 'My heart is filled with regret,' Stars and Stripes reports.

Justin Castellanos, 24, (pictured )who was based in the district's Camp Schwab, pleaded guilty in May to raping the 40-year-old victim in his hotel room in Naha, south Japan on March 13

Justin Castellanos, 24, was sentenced to more than two years in jail for raping a Japanese tourist. The incident has inflamed tensions and anti-American military feeling in the area (pictured is a protest against the military)

Prosecutors had sought a four-year jail sentence but sentenced the sailor to the lesser sentence for his early guilty plea.

His family was also ordered to pay $21,789 in restitution to the victim, while the US military was also told to pay $2,842.

Okinawa governor, Takeshi Onaga, said at the time: 'It is a crime which seriously violates human rights of women and should never be tolerated.'

The U.S. Embassy in Tokyo declined to comment about the incident.

Today the 24-year-old was sentenced to spend more than two years in jail, at the district court in Naha, the capital of Okinawa.

But his arrest, and that of an American military contractor on charges of raping and killing a 20-year-old woman, have inflamed anti-U.S. base sentiment on Okinawa.

Kenneth Shinzato, a former U.S. Marine, was arrested in May after the woman's body was found in a wooded area.

His arrest, and that of an American military contractor on charges of raping and killing a 20-year-old woman, have inflamed anti-U.S. base sentiment on Okinawa

Tens of thousands of people rallied last month against the presence of U.S. military bases, many wearing black to mourn the dead woman.

A major focus of the protest was a plan agreed to by the Japanese and U.S. governments to move a Marine Corps air station to a less-populated part of Okinawa. Opponents want the base moved off the island entirely.

Okinawa has a complicated relationship with the U.S.

For over 70 years, since the WWII, American military bases have been stationed in the area to help deter attacks on both Japan and Okinawa.

However, with more than 25,000 members of the U.S. military stationed there, American security takes up around 18 per cent of the island.

This has caused tensions to rise as local people complain that the military presence is unfair and puts their lives in danger.

But their concerns are not without reason as U.S. troops stationed there have previously been convicted of numerous crimes, including assault.

In a Time magazine article from 1949 it was recorded that between March and September 1949, U.S. service members had committed 29 murders, 18 rapes, 16 robberies and 33 assaults against the island's 600,000 residents.

More recently, in 1995, three U.S. servicemen, Rodrico Harp, Kendrick Ledet and Marcus Gill who were stationed in Okinawa, were convicted of raping and abducting a 12-year-old girl.

The case could further fuel anger towards U.S. military in the midst of an ongoing battle regarding plans to relocate the American air base of Futenma (pictured) within Okinawa

And in 2012, two American soldiers were found guilty of raping a Japanese woman who they followed out from a bar.

The new case could further fuel anger towards U.S. military in the midst of an ongoing battle regarding plans to relocate the American air base of Futenma within Okinawa.

The base is currently located in an urban area containing 19 schools and both the U.S. and Tokyo have been trying to move the camp to the coastal area of Henoko on the island.

The Okinawa government recently won a court case with Tokyo over the creation of an alternate base at Henoko.