A loud explosion shook the US city of Nashville, Tennessee, early on Christmas morning, injuring three people and knocking out communications systems across the state. Authorities said they believed the blast was intentional. The FBI is leading the investigation, according to the Associated Press. Metro Nashville Police Department spokesman Don Aaron said police responded to a call of shots fired just before 6 a.m. but found no immediate signs of a shooting, although officers noticed a suspicious vehicle and called for a hazardous unit. While they waited, the vehicle exploded. Police have now released this image of the vehicle arriving at the scene early on Friday. The vehicle blew up outside a building belonging to the telecoms giant AT&T, which also occupies an office tower nearby. Buildings suffered structural damage, windows were blown out, and trees felled. Videos posted on social media showed water from damaged pipes running down walls as alarms howled in the background. Police emergency systems were knocked out across much of Tennessee. Flights out of Nashville International Airport were briefly halted as a result of damage done by the blast but have now resumed. No motive has yet been established, nor do police know who was behind the incident. CCTV footage posted on YouTube appeared to show the moments before the explosion, when a warning was broadcast, saying, "If you can hear this message, evacuate now". A loud bang follows and flames and smoke fill the screen. "It looks like a bomb went off," Nashville Mayor John Cooper said, urging people to stay away from the area.
