TOKYO - Police in the southernmost Japanese prefecture of Okinawa have referred two US Marines to prosecutors on suspicion of committing separate sexual assaults against women, local media reported.

The Okinawa prefectural police referred the cases of the Marines, each in his 20s, to prosecutors on April 7, public broadcaster NHK reported on Wednesday, citing police sources.

One of them allegedly raped a woman in a restroom of a US military base on Okinawa's main island and injured another woman who tried to rescue the victim, who was a resident of Okinawa and a civilian worker at the base in March, the report said.

READ MORE: US, Japanese naval ships dock at Japan's Ishigaki port, sparking protests

The other Marine is suspected of sexually assaulting a female acquaintance in January, it added.

Both incidents came to light when the victims consulted police.

The suspects, both in the hands of US authorities, were questioned by the Japanese police on a voluntary basis. Police have not disclosed whether the suspects admitted to the charges, saying such a disclosure would hinder investigations.

Speaking to reporters on Wednesday, Okinawa Governor Denny Tamaki said, "It is very deplorable. We'll strongly urge the US military to take measures that would be effective to prevent a similar incident."

READ MORE: Japan urges US military to take actions to prevent sexual assaults in Okinawa

Last Friday, the US military and local police carried out a joint patrol in entertainment districts in the city of Okinawa as part of efforts to prevent sexual crimes involving American military personnel.

The island of Okinawa hosts 70 percent of all the US military bases in Japan while accounting for only 0.6 percent of the country's total land area. Crimes committed by US service members and nonmilitary personnel have been a constant source of grievance for locals.