UPDATE 1:56 p.m. ET: The Montgomery County Police Department said police operations at Walter Reed are complete and there is no evidence of any gun discharge.

Walter Reed UPDATE: Police operations are complete, there is no evidence of a firearm discharge. Normal operations expected to resume soon

— Montgomery Co Police (@mcpnews) July 6, 2015

UPDATE 1:10 p.m. ET: A police official told reporters that there is no indication of a shooting or any injuries at Walter Reed.

Authorities are still completing their search of the facility.

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Security officers are responding to an unconfirmed report of an active shooter at Walter Reed military hospital outside Washington, D.C.

The Montgomery County Police Department said a call came in at 10:48 a.m. about a single gunshot heard on the campus.

Personnel have been ordered to shelter in place, the U.S. Navy's Twitter feed said.

News cameras overhead showed some people being escorted out with their hands up.

MCP ASSISTING Walter Reed Medical Center in Bethesda with report of single shot heard on their campus.

— Montgomery Co Police (@mcpnews)

July 6, 2015

MCP officers on the scene of Walter Reed. Officers have not confirmed initial report of single shot heard. Working with federal partners.

— Montgomery Co Police (@mcpnews) July 6, 2015

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

#BREAKING: #USNavy DOD, NIH and County security personnel responding to unconfirmed active shooter report at Walter Reed/Bethesda. (1/2)

— U.S. Navy (@USNavy) July 6, 2015

(2/2) #BREAKING: Walter Reed/Bethesda personnel sheltering in place. Cannot confirm any incidents, injuries or causalities. MTF.

— U.S. Navy (@USNavy) July 6, 2015

Developing.