RAPID CITY, S.D. (AP) — Ellsworth Air Force Base in South Dakota and the Minneapolis St. Paul Air Reserve Base in Minnesota are among nine U.S. Air Force bases in the world that have been categorized as a “red” installation due to the rise of active COVID-19 cases in areas surrounding the bases.

The U.S. Department of Defense says the red categorization means any civilian or service member would have to meet specific requirements or have an approved waiver to either leave the bases for another military installation or arrive for duty. Department officials won’t comment on the number of coronavirus cases on bases.