FAIRFIELD (CBS13) – Travis Air Force Base officials said they are currently monitoring four positive cases of coronavirus.

A week ago, base officials announced two positive cases of coronavirus involving an active-duty airman and a dependent of a service member.

The base said all of the individuals are being monitored at their residences off base and no confirmed cases are on the installation.

“The base remains in Health Protection Condition Charlie, or HPCON C, and operating with mission essential reporting only,” the base said in a series of tweets. “Team Travis members and families are encouraged to follow state and county guidance to remain in their homes except for necessary movement.”

No further details on the new cases were released.