A 27-year-old U.S. Marine in Japan's Okinawa Prefecture has been indicted for allegedly raping a woman and injuring another in a U.S. military base restroom last month, according to local prosecutors.

Austin Wedington, who was under custody by the U.S. military in line with the bilateral Status of Forces Agreement, was handed over to Japanese authorities on Wednesday. The accord governs the legal status and conduct of U.S. military personnel in Japan.

The prosecutors have not disclosed Wedington's response to the allegations. The assault allegedly occurred in the central part of the main island of Okinawa.

Multiple sexual violence cases by U.S. service members in Okinawa have come to light since June last year, leading to four indictments to date. The southern island prefecture hosts the bulk of U.S. military facilities in Japan.

"There have been ongoing sexual assaults by U.S. military personnel despite our call for swift preventative measures," said Okinawa Gov Denny Tamaki.

"We cannot help but have doubts regarding the education and management of U.S. military personnel. We strongly urge the implementation of more effective countermeasures," he added.

According to the indictment, Wedington choked a female civilian worker in a base lavatory before sexually assaulting her against a stall door and then stomped on the face of the woman who tried to rescue her.

Okinawa police voluntarily questioned Wedington after receiving a report. His case was referred to prosecutors on April 7.

U.S. Ambassador to Japan George Glass said in a statement that he was "disturbed" by the allegations, adding that it does not "reflect the values of the tens of thousands of U.S. service members who serve here honorably."

The indictment comes as the U.S. forces and the Japanese government prepare to hold the first meeting of a forum on May 9 to "address a range of issues and improve community relations."

The forum had been created to strengthen cooperation among the U.S. military, the central Japanese government and Okinawa's government and local residents as part of efforts to prevent sexual crimes involving American military personnel.

Revelations last year by media that the central government had failed to disclose alleged sexual assault cases involving U.S. military members angered locals.