In a major outbreak that sparked outrage among local authorities, hundreds of U.S. Marines deployed at two military bases in Japan have been infected with the coronavirus.

Since 7 July, over 60 of the specialist troops stationed on Okinawa's southern island have tested positive of COVID-19.  

The two bases - Camp Hansen and Futenma Marine Corps Air Station - have now been placed under lockdown.

But the infection has triggered considerable anger in the country which has managed to contain the virus to a large extent, despite having an elderly population and tightly packed towns.

Japanese authorities are demanding an explanation from the U.S. after the massive coronavirus outbreak. Sixty-one Marines have contracted the virus in recent days, the Guardian newspaper reported, spread across the two military installations in the archipelago - which has long been an American military stronghold in the eastern Pacific.

The governor of Japan's Okinawa island demanded a senior U.S. military commander take a more rigid prevention containment steps and transparency hours after authorities were notified of the infections.

Gov. Denny Tamaki, in telephone conversations on Saturday with Lt. Gen. Stacy Clardy, commander of 3rd Marine Expeditionary Force, demanded the U.S. military ramp up prevention measures to the highest levels, stop deploying personnel from the U.S. to Okinawa and lock the bases.

Tamaki is half-American, being born to a father in the U.S. military and a Japanese mother. He is the first Asian-American to be elected into the Japanese House of Representatives.

Any Marine soldier arriving in Japan, and those who show symptoms of the virus or have made contact with anyone who is suspected to have the disease, are placed in a so-called restriction-of-movement status, 1st Lt. Ryan Bruce, a 3rd Marine Expeditionary Force spokesperson, disclosed.

Concerns have been elevated as several American servicemen who arrived in the country had stayed at an off-base hotel prior to being transferred to the two camps last week.

Marine Forces-Japan has since been placed in health protection status "Bravo," Bruce said, which includes social distancing and face-covering protocols and restricted off-base activities.

According to Bruce, the expeditionary force continues to coordinate closely with members of the Okinawan authorities, providing information regarding any new infections through official health channels.

Okinawa is home to over 50 percent of around 50,000 American soldiers in the country under a bilateral security accord.

The people there have long complained about noise, pollution and even crimes arising from the military facilities. Excluding the U.S.coronavirus outbreak, Okinawa has had only 150 cases of the disease in total, until the latest outbreak.