Human remains found near Nashville explosion site in US

"If you can hear this message, evacuate now," the warning broadcast from the RV said. Officials have no information about whether anyone was inside the RV when it exploded, according to MNPD spokesperson Don Aaron, who also said "significant damage has been done to the infrastructure" on the street where the blast occurred.

Meanwhile, the Department of Justice (DOJ) said in the statement that Acting Attorney General Jeffrey Rosen has been briefed on the explosion "and directed that all DOJ resources be made available to assist in the investigation."

Nashville Fire spokesman Joseph Pleasant said three people had been transported to hospital, all suffering injuries that were not critical.

Images and videos taken in the area showed flames and smoke caused by the blast, which police said damaged several buildings.