Amid growing anger among the local populace, more cases of sexual abuse by U.S. forces deployed in Japan have emerged.
Tokyo expressed "regret" and said such incidents "cannot be justified."
Hayashi Yoshimasa, government spokesman, revealed at a news conference in Tokyo that five cases of sexual abuse by U.S. forces were detected last year in Japan.
"Since last year, there have been sexual assault cases without any consent," said Yoshimasa, according to a video record of the news conference.
"There are five of those cases that have not been reported (because) they were not prosecuted," Yoshimasa said, urging the U.S. forces in Japan to prevent such incidents from happening again.
He said: "It is indeed regrettable that there were sexual assault cases involving U.S. soldiers in Okinawa province and those instances might be the source of great concern for the residents."
The revelation of three more cases by the Japanese government comes on the heels of two sexual assault cases by the American soldiers in Japan that came fore last week.
Police in Okinawa province admitted Tuesday they did disclose to public these three sexual abuse cases.
"We have no intention of hiding an incident involving the U.S. military" from provincial authorities, the police clarified.
Last week, it came to fore prosecutors had indicted a U.S. Marine Jamel Clayton for attempted rape and injuring a woman.
Clayton was arrested in May and indicted by the Naha district public prosecutor's office June 17.
Prosecutors last week also indicted a U.S. soldier Brennon Washington, 25, for the alleged sexual assault and kidnapping of a minor last December.
Okinawa provincial authorities last week lodged protests with the U.S. forces for the incidents in the region, saying it was "causing concern for people who are forced to live next to U.S. bases."
They said there was a delay in notifying provincial authorities about the incident.
Japanese Foreign Ministry reportedly knew about the cases but did not alert the provincial government.
More than 50,000 U.S. soldiers have been deployed in Japan under a bilateral defense pact since the end of World War II in 1945.
Pentagon has "regretted" the expose of sexual assault by the American soldiers on Japanese soil and said the U.S. Defense Secretary Lloyd Austin was "closely" monitoring the developments.
