All clear at Joint Base Andrews, after 'active shooter' lockdown

US military Joint Base Andrews, just outside of Washington, DC, was put on lockdown due to an active shooter reportedly barricaded inside the medical center. A "shelter in place" order went into effect at 9 a.m. local time.

Known as "America's airfield," Andrews is the home base of Air Force One, the airplane used by US presidents. It is located in Maryland, four miles southeast of Washington, DC.  Read more.