Police searching home of ‘person of interest’ in mystery Christmas explosion in Nashville

FBI ‘looking at every possible motive’ as evidence collection continues while Tennessee governor requests emergency declaration over bomb’s ‘direct’ impact to telecommunications

No arrests have been made and no suspects are in custody a day after a Christmas morning blast in Nashville, but law enforcement agencies have identified "a number of individuals" that could be connected to the explosion.

Police have identified at one person of interest and are searching a home associated with that person, according to the Associated Press.

Several law enforcement agencies are continuing to respond to calls for information and collect evidence that was sprayed across the city’s downtown, after a parked recreational vehicle (RV) broadcast warnings over a loudspeaker moments before it exploded on Friday morning, injuring at least three people and destroying several nearby buildings and businesses near 2nd Avenue and Commerce Streets.

FBI Special Agent Douglas Korneski told reporters on Saturday that law enforcement cannot confirm the names of anyone the agency has potentially identified, but added that “there are a number of individuals that we're looking at.”

“We're looking at every possible motive,” he said.

US Attorney Don Cochran said law enforcement was "continuing to follow every lead we have” as it responds to 500 calls with information.

He compared the evidence collection process  to a “giant jigsaw puzzle created by a bomb."

Police believe they have discovered “tissue” near the scene they believe could be human remains.

The FBI, Metro Nashville Police Department the Bureau of Alcohol, Tobacco and Firearms are seeking information about the owner or operator of the RV as well as information from people who were in the area around 1am CST on Thursday night.

Law enforcement has identified an RV connected to a mysterious explosion in downtown Nashville on Christmas morning. (FBI)

Police arrived downtown following reports of shots fired around 5.30am on Friday, but they arrived to find the RV parked outside an AT&T building. The RV then broadcast a warning: “Evacuate now. There is a bomb. A bomb is in this vehicle and will explode."

The looped message and a 15-minute countdown continued, until 6.30am, when a massive explosion caught on nearby surveillance footage captured a bomb-like eruption that reportedly knocked out communications systems in several areas and caused “telecommunications issues” that disrupted flights at Nashville International Airport.

Three people were hospitalised and are in stable condition, and more than 40 businesses were impacted.

Tennessee Governor Bill Lee requested a federal emergency declaration on Saturday morning to support ongoing relief efforts, citing the “direct” impact on AT&T’s communications systems across the state as well as parts of Alabama and Kentucky.

The governor said the impacts affected residential service as well as 20 public safety and 9-1-1 call centres.