Two law enforcement officials told The Associated Press on Saturday that a person of interest has been identified in connection with Friday's early morning blast in Nashville, Tennessee and that a home was being searched.

The Federal Bureau of Investigations (FBI) is now leading the investigation. FBI special agent Douglas Korneski said 250 agents and analysts were making progress in the search for the person or people responsible.

"It's just going to take us some time,'' Korneski said. "Our investigative team is turning over every stone to understand who did this and why," he added.

Nashville police are uncertain whether anyone was inside the motor home at the moment of the explosion, which sent three people to hospital. But investigators have found tissue that they "believe could be human remains," Police Chief John Drake said at a briefing on Friday.

"We will continue to examine that," Drake told reporters. "There are no fatalities we know of." Police have said it "appears to have been an intentional act."

The blast also caused damage to at least 40 buildings. A telecoms office was affected and the resulting damage has caused sweeping communications outages in the area and beyond.

Nashville's downtown was largely deserted at the time of the explosion, due to the early hour and the Christmas holiday when most businesses are closed. 

How did events unfold?

Early Friday, authorities responded to a report of shots fired at the scene. There, they encountered a motor home, also known as a recreational vehicle or RV.

The RV was blaring a recording that said a potential bomb would detonate in 15 minutes. This prompted the police to evacuate nearby buildings and call in a bomb squad. Shortly afterward, the motor home exploded.

The detonation happened near an office of telecommunications company AT&T. "We do not know if that was a coincidence, or if that was the intention," said police spokesman Don Aaron.

AT&T has confirmed that the blast caused outages, but declined to say how widespread they were. The company said its service restoration efforts were facing several challenges, including a fire that "reignited overnight and led to the evacuation of the building.''

"Our teams continue to work around the clock on recovery efforts from yesterday morning's explosion in Nashville,'' the company said Saturday.

Police emergency systems in Tennessee, Kentucky and Alabama, as well as Nashville's COVID-19 community hotline and a handful of hospital systems, were all affected and out of service due to the outage.

Eyewitness: 'I got my cat in her carrier' 

Local resident Betsy Williams told DW about her experience of fleeing her apartment ahead of the explosion. 

After hearing what she described as "very loud" gunshots, she noticed a white RV parked right across the street.

"Coming from the RV was a computerized voice message saying, evacuate now, evacuate now. This vehicle has a bomb. It will explode, evacuate now."

"Then it started on a countdown where it said this vehicle will explode in 15 minutes and then in 14 minutes. Then we started really gathering our things up, I got my cat in her carrier. I got my son who was staying in another apartment that was also overlooking Second Avenue."

She told DW she thinks she would have been killed or severely injured if she had not left her apartment because she was sitting next to her window.

"We raised the window so we could really clearly hear what the RV was saying," she told DW. The eyewitness also praised the police for their quick response.

How have politicians reacted?

US President Donald Trump has been briefed about the situation in Nashville but has yet to comment publicly, according to White House spokesperson Judd Deere.

The Justice Department said Acting Attorney General Jeff Rosen has also been briefed and had directed all department resources be made available to help with the investigation. 

Tennessee Governor Bill Lee said on Twitter that the state is ready to provide the city with the resources necessary ''to determine what happened and who was responsible.'' 

"This morning's attack on our community was intended to create chaos and fear in this season of peace and hope. But Nashvillians have proven time and time again that the spirit of our city cannot be broken," Cooper said at a news conference.

kmm, jcg/aw (AP, Reuters, AFP)