A large explosion ripped through part of downtown Nashville early on Christmas morning. Police believe the explosion was intentional.

The Metro Nashville Office of Emergency Management told local broadcaster News 2 that a parked RV exploded around 6:30am and damaged at least 20 surrounding buildings. 

Nashville Fire spokesman Joseph Pleasant said three people were taken to the hospital, though none were in critical condition. 

The FBI and the Bureau of Alcohol Tobacco and Firearms are investigating. The Tennessee Bureau of Investigation is also aiding the investigation. Police dogs trained to sniff out accelerants are being used to search for other potential bombs. 

The Tennessean reported that several people were taken to the department’s central precinct for questioning, but police have declined to provide further details regarding those individuals. 

Nashville police announced that a 10-block radius of downtown streets would be closed as they investigate the scene further. A spokeswoman for the Metro Nashville Police Department said the site of the explosion was an “active scene.” 

Metro Police Spokesman Don Aaron said officers went door-to-door before the explosion to evacuate residents who lived close to where the RV was parked. 

Officers also apparently turned away a man who was walking his dog toward the RV just before it exploded. 

The police were called to check out a suspicious vehicle parked outside the AT&T office building - the city’s largest skyscraper - at 6am this morning, and called a hazardous devices unit to investigate.

The explosion went off a half an hour later. 

ABC News reported that the initial call to the Nashville police reported gunfire. Police confirmed there was no gunfire in the area, but did discover the RV, which prompted them to alert the bomb squad. 

A Department of Justice spokesperson said that it had been instructed to make “all DOJ resources available to assist in the investigation.”

A man who lives nearby, Buck McCoy, posted a video to Facebook showing the aftermath of the explosion. His windows are completely blown out and water is pouring down from the ceiling of his home. 

Alarms whir in the background, barely masking the cries of others whose Christmas mornings was ruined by the blast. 

Black smoke billows into the air outside his home, rising from a vehicle fire on the ground outside. 

“All my windows, every single one of them got blown into the next room. If I had been standing there it would have been horrible,” he told the Associated Press. “It felt like a bomb. It was that big,” he told The Associated Press.

John Cooper, the city’s mayor, told CNN that he was aware of the explosion and was on his way to the scene. 

"I do know emergency services are calling in our help, all our specialties, to investigate the cause of the explosion and I'm sure more information will be posted soon," Mr Cooper said.

The explosion occurred in the heart of the city’s historic old town, which is home to its hospitality and tourist district. 

Sen. Marsha Blackburn of Tennessee wrote in a twee that she was “closely monitoring the situation.”

The state’s governor, Bill Lee, called for prayers and said the state would provide any resources needed by investigators to determine the cause of the explosion. 

Donald Trump has also been briefed on the explosion, according to the deputy White House press secretary Judd Deere.