BERLIN: Face masks should be worn not only indoors but outdoors too to prevent coronavirus infections if social distancing cannot be maintained, the head of Germany's disease control institute said Tuesday.

Lothar Wieler said basic hygiene rules such as handwashing and distancing must be followed to keep infections down, and "if one can't ensure 1.5 metres distancing, then we recommend masks -- not just in closed areas but also in the open."