The scene at Joint Base Andrews has been given the all-clear.
An active shooter incident was reported at the base's Malcolm Grow Medical Facility in Camp Springs, Maryland, around 9 am. EST Thursday, the base says.
The base was put into lockdown. By 10:40 a.m., first responders determined there was no threat to the base or personnel.
It was miscommunication
The report of a shooter came as the base was scheduled to conduct a no-notice active shooter exercise late Thursday morning.
"However, reports of a real-world active shooter situation at the medical facility were miscommunicated before the exercise was able to begin," the base said in an update on its website.
The security forces emergency services team, which was conducting a routine inspection of the medical facility, was misidentified, and that caused the distress call to the base defense operations center.
Col. Brad Hoagland, 11th Wing and JBA commander, said they take "all threats seriously and reacted to ensure the security of those on the base."
"Fortunately, this was not a life-threatening situation," Hoagland added.
More on Joint Base Andrews
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Joint Base Andrews is a U.S. military facility that's run by the Air Force 11th Wing.
It used to be two separate entities known as Andrews Air Force Base and Naval Air Facility Washington, but the two merged in 2009 to create Joint Base Andrews.
It's officially the home of Air Force One, and the base is often used for the travel of higher-ups in the government and military.
Approximately 17,000 people work at the base, which is about 20 miles southeast of Washington D.C., DC Military says.