BETHESDA, Md. (WJZ) — Naval Support Activity Bethesda, a Naval base in Bethesda, issued a shelter in place for over four hours Wednesday for a bomb threat at Walter Reed National Military Medical Center.

The shelter in place, put in effect shortly after 9 a.m., remained in effect for the entire installation for just over three hours. Just after noon, the order was lifted for all locations except for Walter Reed.

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The shelter in place for all buildings was lifted at 1:18 p.m.

The installation said it received a phone call around 8:45 a.m. from an anonymous source saying there is a bomb at or near the building.

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All gates are closed to incoming traffic, gates one and three are open for outbound traffic.

All patient appointments have been canceled at the hospital.

There was initially an active shooter threat when the shelter in place was issued around 9 a.m., but that threat was dismissed around 10 a.m.

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According to the Walter Reed’s website, the facility formerly known as the National Naval Medical Center has cared for every President of the United States over the years, as well as other national leaders.

CBS Baltimore Staff