TOKYO >> An outbreak of coronavirus cases on U.S. military bases in Okinawa, Japan, has alarmed the island’s local population, which at times has been at odds with the Americans stationed there and has otherwise been successful in limiting COVID-19.

The U.S. Marine Corps, which has about 20,000 troops stationed on the island, reported 94 confirmed cases to the prefectural government and said it had instituted strict measures in all 33 installations in the region.

Denny Tamaki, the governor of Okinawa, said he was shocked by the number of infections and said it was “extremely regrettable” that so many cases had emerged among U.S. troops and affiliated personnel in less than a week. Excluding the American cases, Okinawa has recorded just 148 infections since February.

Tamaki added that he had “strong doubts” about the prevention measures reported by the United States.

Japan, which has been relatively successful in containing the virus, has also experienced a recent surge of new cases concentrated in Tokyo, where a state of emergency was lifted at the end of May. Tokyo reported two consecutive days of record daily infections last week, with a large number of cases among people in their 20s and 30s who worked in or had visited venues in Tokyo’s nightlife districts.

The U.S. military in South Korea also announced Monday that 11 troops had tested positive upon arrival from the United States. The U.S. military has struggled with outbreaks among its troops, with a major cluster of infections in March on the aircraft carrier Theodore Roosevelt.

The Japanese military, by contrast, has reported just 14 cases among its defense forces, all of whom are thought to have contracted the virus in their communities rather than while deployed.

The cases in Okinawa are a new strain on relations between the military and the local government, where the presence of U.S. bases, dating to the end of World War II, has been an ongoing source of friction. Citizens have long complained of noise, crime and aircraft accidents, and have repeatedly questioned why nearly half of the 55,000 U.S. troops in Japan — which include personnel from all of the military branches — are stationed on Okinawa.

One of the bases where a number of the recent coronavirus cases have been recorded, Marine Corps Air Station Futenma, is the subject of a contentious plan to relocate the base’s operations from central Okinawa to a less-populated coastal area where construction is underway.

The Japanese central government considers the bases essential to the country’s security, and many citizens and businesses on Okinawa welcome the troops as customers and neighbors.

When news of infections first started emerging from the bases, both the governor and the Okinawa prefectural assembly demanded more information from the Marine Corps about the number of cases, which troubled Okinawan officials and residents who feared they may have unknowingly come into contact with infected troops.

“When anything like this happens, when the military doesn’t provide essential information of how many people are infected or where they are from or where they have been outside of the base, the Okinawan people are really scared and frustrated and disappointed,” said Manabu Sato, professor of political science at Okinawa International University, which overlooks the Marine Corps Air Station Futenma.

“I’m scared,” said Tomonari Kiyuna, a worker at a noodle shop in Chatan, a neighborhood on Okinawa frequented by U.S. soldiers. “We’re very careful, wearing masks, washing hands, and sanitizing,” Kiyuna said. “I want them to disclose the information. They are Americans but they are staying in Okinawa, Japan. Okinawans or the Japanese people have the right to know” about infections stemming from the bases.

Yoshihide Suga, chief Cabinet secretary to Prime Minister Shinzo Abe, said in a news conference that the government had “received the necessary information from the U.S. side, such as numbers of infected personnel and facilities affected.”

Tamaki said he was concerned that the soldiers had spread infections during celebrations on July Fourth.

“There is information that the U.S. Forces personnel went out to the nightlife districts and had beach parties outside of the bases on July 4,” Tamaki said in a statement Saturday.

He requested that the military stop transferring new troops from the United States, where case numbers are surging.

Under measures instituted over the weekend, all U.S. troops and families on Okinawa are prohibited from leaving base without approval from commanders. They cannot visit restaurants, even for takeout, travel on public transit, use child-care facilities or exercise off base. Futenma and Camp Hansen, where the largest number of cases have been reported, are effectively on lockdown, U.S. officials said.

Throughout Japan, all troops and families arriving from the United States must quarantine for 14 days, said Col. Robert A. Firman, public affairs director for U.S. Forces Japan.

“That measure will continue for the foreseeable future,” Firman said. “Installation commanders also have the discretion to increase protective measures based on local conditions, and that’s what we are seeing in Okinawa.”

Firman said that military staff must also wear masks in most base facilities, implement social distancing and limit the size of any gatherings. Major Kenneth Kunze, a spokesperson for the Marines on Okinawa, said that “thorough contact tracing is ongoing to identify and isolate those who may have come in contact with infected personnel. Anyone on or off base identified as having been in contact with an infected or suspected infected individual will be notified.”

One of the largest hospitals on Okinawa, Chubu Hospital, has offered free testing to anyone who is concerned they may have been exposed to the virus. So far, the hospital has tested 130 people since news of the base outbreaks.

In a Facebook post, Yoshihiro Takayama, a doctor in the Infectious Disease and Public Health Department at Chubu Hospital, warned against blaming the military for the spread of the virus.

“People tend to misunderstand that the U.S. service personnel spread the virus as many cases were found among them,” Takayama wrote. “But I don’t think so. It’s assumed that they were infected on July 4, judging from the confirmed date. But it’s still unknown from whom they got infected as epidemiological information is not shared. They could have been infected from contact with Japanese residents or among service personnel. It is supposed that there are multiple routes, but we should not have preconceptions.”

He added that people had “visited many bars, danced in groups shoulder to shoulder and shared wine bottles,” including both U.S. military personnel and local residents.

In Chatan, where there are many bars frequented by the Americans, businesses noticed a downturn as the base lockdowns went into effect.

“We saw a huge drop in customers yesterday, especially Americans,” said Itaru Maeshiro, owner of the Transit Cafe, where about one-third of regular customers are U.S. military personnel.

At a sushi shop in Chatan, chef Kazuya Kaneshi said that the strict lockdown measures were tough for business.

“But we don’t want infections at the same time,” he said. “If infections expand in the whole of Okinawa, it will be a huge problem.”