The crew members of the USS Ronald Reagan, a Nimitz-class nuclear-powered super carrier, saluting is seen behind the national flag of the U.S. as it arrives at the U.S. naval base in Yokosuka, south of Tokyo, Japan, October 1, 2015. REUTERS/Yuya Shino

TOKYO (Reuters) - The U.S. Navy slapped a drinking ban on sailors stationed in Japan on Monday and halted off base liberty after police arrested a U.S. sailor on the southern island of Okinawa on suspicion of drunk driving following a car crash that injured two people.

“For decades we have enjoyed a strong relationship with the people of Japan. It is imperative that each sailor understand how our actions affect that relationship and the U.S. Japan alliance as a whole,” Rear Admiral Matthew Carter, commander of U.S. naval forces in Japan said in a press release on Monday.

The United States has 18,600 sailors stationed in Japan.

The latest incident came as the U.S. military observes a 30-day mourning period at bases on Okinawa after an American civilian working for the U.S. military there was arrested on suspicion of dumping the body of a 20-year-old Japanese woman.

Renewed anger among residents in Okinawa at the U.S. military presence threatens a plan to relocate the U.S. Marines’ Futenma air base to a less populous part of Okinawa, which was agreed in 1995 after the rape of a Japanese schoolgirl by U.S. military personnel sparked huge anti-base demonstrations.

Okinawa’s governor and many residents want the marines off the island.

All U.S. Navy sailors in Japan will be kept on base and banned from drinking until “all personnel understand the impact of responsible behavior on the U.S.-Japan alliance,” the press release said. “Sailors living off base will be allowed to travel to and from base and conduct only “essential activities.”

The restrictions do not apply to family members and civilian U.S. contractors, which brings the total number of people to 35,000, but they are being encouraged to observe the rules “in a spirit of solidarity,” a spokesman for the U.S. Navy said.