TOKYO — Dozens of U.S. Marines at two bases on the southern Japanese island of Okinawa have been infected with the coronavirus in what is feared to be a massive outbreak, Okinawa’s governor said Saturday, demanding an adequate explanation from the U.S. military.

Gov. Denny Tamaki said he could say only that a “few dozen” cases had been found recently because the U.S. military asked that the exact figure not be released.

The outbreaks occurred at Marine Corps Air Station Futenma and Camp Hansen, Tamaki said.

Local media, citing unnamed sources, said about 60 people had been infected.

“Okinawans are shocked by what we were told (by the U.S. military),” Tamaki told a news conference. “We now have strong doubts that the U.S. military has taken adequate disease prevention measures.”

Tamaki demanded transparency in the latest development and said he planned to request talks between the U.S. military and Okinawan officials. He said Okinawan officials also asked the Japanese government to demand that the U.S. provide details including the number of cases, seal off Futenma and Camp Hansen, and step up preventive measures on base.

Okinawan officials made similar requests to the U.S. military on Friday in order to address local residents’ concerns, Tamaki said.

The Marines said in a statement Friday that the troops were taking additional protective measures to limit the spread of the coronavirus and were restricting off-base activities.

The Marines did not immediately respond Saturday to an Associated Press inquiry about the latest outbreak.

Okinawa is home to more than half of about 50,000 American troops based in Japan under a bilateral security pact.