The Pentagon on Sunday tightened its policy on face masks to stop the spread of coronavirus, issuing new guidance that requires all military and civilian personnel, along with family members, contractors and guests on military installations, to wear a “cloth face recovering” if they’re unable to stay at least six feet away from others.

The new protocol, Defense Secretary Mark Esper said in a memo, is designed to bring the Pentagon in line with Centers for Disease Control and Prevention recommendations that masks be used to prevent transmission of the virus.

“Effective immediately, to the extent practical, all individuals on DoD property, installations, and facilities will wear cloth face coverings when they cannot maintain six feet of social distance in public areas or work centers,” Mr. Esper says in the memo, adding that the guidance does not apply to a service member’s home on a military base.

Each military department, he said, will soon issue formal “guidance on wear” for service members.

“As an interim measure, all individuals are encouraged to fashion face coverings from household items or common materials, such as clean T-shirts or other clean cloths that can cover the nose and mouth area,” the memo reads.