The Pentagon put all bases on a higher alert status for the Fourth of July because of threats from ISIS. So when the call came in Thursday morning for a report of shots fired at the Washington Navy Yard, some in the public and law enforcement feared terrorism until they got the all clear.
FBI, D.C. police, U.S. Marshals, Capitol police and many others in law enforcement descended onto this military base.
"You have a city that has a lot of local, federal law enforcement assets that are very well coordinated," said D.C. Police Chief Cathy Lanier.
The commander of the Navy Installations Command was pleased with the joint effort.
"I would like to thank the mayor, the police chief and all the first responders for your quick response this morning," said Vice Admiral Dixon Smith.
The ISIS threat goes beyond military bases for July 4th. Homeland Security and the FBI both issued alerts to local law enforcement about a possible terrorist attack on Independence Day.
"We take every event here in Washington very seriously and our posture remains extremely high for all special events and it will continue for the Fourth," said Chief Lanier.
Emotions ran high on Thursday as no one knew what happened inside the walls for almost four hours. It wasn't until after 11 a.m. that the mayor and police chief came to the media to calm the nerves of the public.
"When we talk to our residents and visitors who want to celebrate Independence Day in the District of Columbia, it should be very clear to everybody that we take clear and credible threats or calls from our citizens and employees very, very seriously," said D.C. Mayor Muriel Bowser.
Two officers who were inside the Navy Yard complex when this all happened said the woman who made the report actually heard construction sounds in the Navy Yard. The woman called security, who then relayed the information to police as possible gunshots.
However, officials are not blaming woman for making the call that started all this. They said she was doing what she has been taught to do -- if you see something, say something -- and she did just that in this situation.