U.S. Naval Support Activity Bethesda in Maryland was on lockdown on Wednesday due to a bomb threat and an active shooter investigation, the naval base said on Twitter.

All personnel were ordered to shelter in place after the base received an anonymous phone call around 8:45 a.m. saying there was a bomb at or near the site, the base said.

NSA Bethesda houses Walter Reed National Military Medical Center.

(Reporting by Gabriella Borter) ((Gabriella.Borter@thomsonreuters.com; 646 223 5942;))