A parked recreational vehicle exploded in downtown Nashville, Tennessee, on Christmas morning, in what Nashville police believe was an “intentional act.”

a blurry photo of a busy city street: A vehicle burns near the site of an explosion in the area of Second and Commerce in Nashville, Dec. 25, 2020.© Andrew Nelles/Tennessean.com/USA Today Network via Reuters A vehicle burns near the site of an explosion in the area of Second and Commerce in Nashville, Dec. 25, 2020.a group of people walking down a dirt road: Emergency personnel work near the scene of an explosion in downtown Nashville, Tenn., Dec. 25, 2020.Emergency personnel work near the scene of an explosion in downtown Nashville, Tenn., Dec. 25, 2020.Nashville police officers were at first called to a report of shots fired, police said. There was no evidence of shots fired, but “there were announcements coming” from an RV saying a potential bomb would detonate within 15 minutes, police said.

Officers were working to evacuate nearby buildings when, around 6:30 a.m., the RV exploded, blowing out the windows of nearby buildings.

© Andrew Nelles/Tennessean.com/USA Today Network via Reuters A vehicle burns near the site of an explosion in the area of Second and Commerce in Nashville, Dec. 25, 2020.a person standing in front of a brick building: Debris scattered a near the scene of an explosion in downtown Nashville, Tenn., Dec. 25, 2020.Debris scattered a near the scene of an explosion in downtown Nashville, Tenn., Dec. 25, 2020.The explosion knocked one officer to the ground. Another officer sustained temporary hearing loss.

Three people were taken to the hospital with minor injuries. No significant injuries have been reported.

It’s not known whether anyone was in the RV when it exploded, authorities said.

Several buildings suffered structural damage, authorities said.

a group of people standing on top of a snow covered road: Emergency personnel work at the scene of an explosion in downtown Nashville, Tenn., Dec. 25, 2020.Emergency personnel work at the scene of an explosion in downtown Nashville, Tenn., Dec. 25, 2020.In the search for the suspect, there are “investigate leads to be pursued” and “technical work that needs to happen,” the FBI said.

“We will find out what happened here,” the FBI said.

The FBI, the lead investigating agency, asks anyone with information to submit a tip on the FBI website.

Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives have also responded.

President Donald Trump, acting Secretary of Homeland Security Chad Wolf and acting Attorney General Jeff Rosen have been briefed on the incident.

Authorities said they are not aware of other imminent danger. K-9 dogs are sweeping the downtown area as a precaution, police said.

The debris field extends for at least a few blocks. Streets around the exploded vehicle have been closed down.