Police say there is no indication there was a shooting at Walter Reed National Military Medical Center on Monday after an unconfirmed report of an active shooter on the hospital's Bethesda, Md., campus triggered a lockdown.







#WalterReed employees were told to shelter in place via a text alert. http://t.co/bwXbv77oFq pic.twitter.com/dYmZiVW2bx — NBCWashington (@nbcwashington) July 6, 2015



According to police in Montgomery County, a 911 caller reported hearing one shot fired inside Building 1 at approximately 10:48 a.m.









Call received at approx. 10:48 a.m. for report of single shot heard on Walter Reed campus. Officers have not confirmed initial report. — Montgomery Co Police (@mcpnews) July 6, 2015



The facility was placed on lockdown while local police and federal agents searched the area.









UPDATE on unconfirmed report of shot fired at #WalterReed / Bethesda. Security searching buildings. No confirmation of incident. — U.S. Navy (@USNavy) July 6, 2015



Employees were seen being evacuated from a building with their hands raised.









#BreakingNews watching armed personnel escort #WalterReed employees out, report of a gunshot heard pic.twitter.com/HCAPgWBC2q — Brad Freitas (@NewsChopperBrad) July 6, 2015



Staffers sheltering in place tweeted updates from inside the facility.



Story continues

Are we sure it wasn't just a car backfiring on/off base? I didn't hear anything on my way in today. https://t.co/fRvRUXtFHV — Heather (@heather_kopf) July 6, 2015



Others called their family members, who relayed messages via Twitter.









my sister asks me to tweet that she's safe & in lockdown, in complete blackness & someone is passing around candy #walterReed @wusa9 — Allison Baughman (@baughwoman) July 6, 2015



Nearby roads were also closed as a precaution.









Rockville pike shut down near #WalterReed where police search after a report of shooter. @wusa9 pic.twitter.com/vZ6PlaJRDI — Hank Silverberg (@HankSilverberg) July 6, 2015



At a 1 p.m. press briefing, Montgomery Capt. Paul Starks said officials were close to completing a sweep of Building 1 and there was "no indication of any kind" that there was a shooting, and no injuries reported.



Once the building is cleared, Starks said, it would searched by bomb-sniffing dogs "out of an abundance of caution."

The sweep was completed at 1:30 p.m., police said.

Last week, a report of possible gunshots heard by an employee at the Washington Navy Yard triggered a massive law enforcement response. But a subsequent search found no evidence a shooting had occurred.

That false alarm came two years after a gunman opened fire inside a building at the Navy Yard, killing 12 people and injuring three others.