Updated

The U.S. military installation housing the Walter Reed National Military Medical Center in Maryland was temporarily placed on lockdown Wednesday after it "received a phone call from an anonymous source stating there is a bomb at or near" one of its buildings, officials say

Naval Support Activity Bethesda first warned in a tweet that "all personnel should shelter in place" and the "public is asked to avoid the area." It added that the reported bomb threat was directed at Building 10 and all gates to the base were closed to non-emergency traffic. 

A map showing the location of the bomb threat in the complex housing the Walter Reed National Military Medical Center. (Google Maps)

But Walter Reed Bethesda later tweeted that Naval Support Activity Bethesda "issued the ‘all clear’ from the base wide lockdown/shelter in place."

"All staff and beneficiaries are free to move about the hospital or installation as needed," it added.