SPRING HILL, Tenn. (WKRN) — Authorities reportedly evacuated about 400 people from a large building in Spring Hill after a bomb threat was called in Saturday evening.

According to the Spring Hill Police Department, the Williamson County Emergency Communications Department received a call at approximately 6:10 p.m. on Saturday, March 23 from someone who said they had placed multiple bombs inside of 5000 Northfield lane, which is the old Saturn Headquarters building adjacent to the General Motors plant.

“We have a command center established with partner agencies. We are asking the public to stay away from this building until officers can search the building (it’s very large) to ensure everyone’s safety,” officials said in a statement sent to News 2. “This is a fluid situation and we will update via our Facebook/Twitter page when we have information to give.”

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Authorities said a large boxing event was happening at the building in question, so all spectators — an estimated 400 people — were evacuated.

In addition, bomb squad technicians from Tennessee Highway Patrol (THP) and the Columbia Police Department responded to the scene to search the building and make sure everything was safe.

According to officials, the only building impacted by the situation was the Northfield building, which is about 350,000 square feet.

At 8:21 p.m., a member of the Spring Hill Police Department told News 2 the unattended bag that prompted the evacuation has been deemed safe by THP bomb techs, but officers were still working to ensure there are no other hazards in the building.

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Just after 8:30 p.m., authorities announced the search was complete and spectators would be allowed back into the building.

“Thank you to the Tennessee Highway Patrol, Spring Hill Fire Department, and World Wide Stages Security, who assisted us during this incident. The Columbia Police Department, Tennessee and Nashville International Airport Police also offered resources as well,” the Spring Hill Police Department posted on Facebook. “We will work to investigate the origins of this bomb threat. It appears that this is a “swatting” call. We will work with our state and federal law enforcement partners to determine the origin of this call. More information about “swatting” can be found here: https://www.fbi.gov/…/fbi-las-vegas-federal-fact-friday.

No additional details have been released about this situation.

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This is a developing story. WKRN News 2 will continue to update this article as new information becomes available.