Japanese authorities have accused two US marines stationed in Okinawa of recently raping and assaulting local women.

Police said on Thursday that the latest incidents inside US military bases were in a string of assault cases that have angered local residents.

One of the US marines accused of rape is also suspected of assaulting another woman.

“A US marine in his 20s is suspected of raping a Japanese woman at an American military base in March, and is also suspected of injuring another woman,” a local police official told AFP.

The second marine, also in his 20s, is suspected of raping a Japanese woman at a US base in January, the official said.

Police have referred the two cases to Japan’s judicial officials. The US ambassador to Tokyo pledged to cooperate “fully” with Japanese authorities in the investigations.

Japan’s top government spokesman Yoshimasa Hayashi said in a regular briefing on Thursday that any crime by US troops based in Japan is “unacceptable”, without making any direct reference to the latest incidents.

Okinawa Governor Denny Tamaki has expressed grave concern over the incidents as local authorities struggle to deter sexual and other crimes carried out by the US military personnel based in Japan.

He called the latest cases “deplorable” and said authorities would urge the US military to prevent such happenings.

Relations have long been strained between Okinawans and US marines.

Last year, a total of 80 people connected to the US military were charged in Okinawa for various crimes.

A 21-year-old marine was charged with rape in June last year, just months after prosecutors charged a 25-year-old US marine for allegedly assaulting a girl under 16.

The 1995 gang rape of a 12-year-old girl by three US soldiers in Okinawa prompted a major backlash, with calls for a rethink of the 1960 pact allowing the United States to station troops in Japan.

The United States has around 54,000 military personnel stationed in Japan — mostly on the subtropical southern island of Okinawa, to the east of Taiwan.

The news of the latest sexual assaults came after US troops on Friday joined Japanese officials and residents in Okinawa for a one-off joint nighttime patrol along a downtown street dotted with bars.

The patrol, the first such joint operation since 1973, followed other sexual assault cases in Okinawa involving US marines.