Tokyo, Japan - Japan urged the US to enforce discipline among its troops after a Marine was arrested on suspicion of drunk driving during a curfew in the wake of another serviceman's arrest on a murder charge, the defense minister said on Monday.

US forces on the island of Okinawa were barred from drinking alcohol for two days early last month and faced a 30-day curfew after the murder of a woman allegedly committed by an American Marine.

The case has triggered outrage in Japan and reignited controversy over the heavy US military presence on the southern island.

A second Marine had been arrested over allegations he drove under the influence of alcohol, Defense Minister Shinjiro Koizumi said.

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The arrest took place on Saturday, according to media reports.

"We requested that the US side strictly enforce discipline among its personnel, implement effective measures to prevent a recurrence, and ensure full compliance with the nighttime curfew," Koizumi told reporters.

"We want them to take (the incident) seriously," he added.

The curfew imposed last month required all troops to be back on base or at "an off-base domicile" from midnight to 5:00 AM.

Last week, Japanese prosecutors indicted the Marine accused of murdering a woman in Okinawa.

Prime Minister Sanae Takaichi told lawmakers days after the woman's death that the government had lodged a strong protest with the US, urging their "full cooperation with the investigation" and "strict discipline among US military personnel."

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The Yomiuri Shimbun newspaper reported that, according to the indictment document, the 20-year-old suspect allegedly strangled the woman from Naha in a hotel with a telephone cord on October 3.

The US has around 54,000 military personnel stationed in Japan, mostly on Okinawa.

Foreign Minister Toshimitsu Motegi has previously said that officials were reviewing the off-base code of conduct for US troops in Japan following the alleged killing.

The existing policy, updated in 2024 following a string of sexual assaults by US military personnel in Okinawa, includes a ban on servicemembers drinking in public off base between 1:00 AM and 5:00 AM or going to bars during those hours.