US Forces Korea said Friday that all individuals on its installations will be required to wear masks or cloth face coverings in public spaces to stem the spread of the coronavirus.

Effective Friday, all people at military installations must wear one if they cannot maintain at least 2 meters of social distance in public areas or work centers, USFK said in a release.

The measure will be toughened starting on Saturday, as all individuals on its installations "will be required to wear a cloth face coverings or mask in the Commissary, PX/BX, Shoppette, Food Court and Post Office during HPCON C and C+," it said, citing its Health Protection Condition Levels.

USFK issued the HPCON level of Charlie Plus, or C+, for Camp Humphreys and the Osan Air Base located in Pyeongtaek, some 70 kilometers south of Seoul, while all other USFK installations are operating at HPCON Charlie.

Charlie/C+ is the fourth highest warning level in the five-scale system. If the level is brought a notch hither to HPCON D, wearing masks will be a must at all times outside of residences, according to USFK.

"As a courtesy and sign of solidarity with our host nation communities, all USFK personnel are encouraged to wear cloth face coverings or masks when off installation; the face covering is a visible sign of our commitment to combating COVID-19 and testament to US-ROK Alliance," it added.

USFK then said it will issue two masks per member starting next week.

As of Friday, the US military had reported a total of 21 confirmed virus cases, including two active-duty personnel. (Yonhap)