carlballou/iStockBy EMILY SHAPIRO, AARON KATERKSY, ABC NewsHuman remains have been located at the site where a parked recreational vehicle exploded in downtown Nashville, Tennessee, on Christmas morning, in what Nashville police believe was an “intentional act.”Multiple law enforcement sources tell ABC News that the remains have not been identified, and it was not immediately determined whether they are identifiable. Nashville police officers were at first called to a report of shots fired. There was no evidence of shots fired, but “there were announcements coming” from an RV saying a potential bomb would detonate within 15 minutes, police said. BREAKING: This is the RV that exploded on 2nd Ave N this morning. It arrived on 2nd Ave at 1:22 a.m. Have you seen this vehicle in our area or do you have information about it? Please contact us via Crime Stoppers at 615-742-7463 or online via https://t.co/dVGS7o0m4v. @ATFHQ pic.twitter.com/JNx9sDinAH— Metro Nashville PD (@MNPDNashville) December 25, 2020 The bomb squad was called and the area was evacuated. Around 6:30 a.m., as the bomb squad responded, the RV exploded, blowing out the windows of nearby buildings and leaving extensive damage.MNPD, FBI & ATF investigating the 6:30 a.m. explosion on 2nd Ave N linked to a vehicle. This appears to have been an intentional act. Law enforcement is closing downtown streets as investigation continues. pic.twitter.com/YOfMTaKmTH— Metro Nashville PD (@MNPDNashville) December 25, 2020The explosion knocked one officer to the ground. Another officer sustained temporary hearing loss.Three people were transported to the hospital with minor injuries. No significant injuries have been reported.It’s not known whether anyone was in the RV when it exploded, authorities said.Nashville International Airport said it was temporarily halting flights Friday afternoon “due to telecommunications issues” associated with the blast.AT&T said service has been impacted in Nashville and surrounding areas because of damage to its facilities from the explosion.Communications capabilities came back in the tower about an hour after the ground stop was issued and service resumed, the Federal Aviation Administration said.Resident Buck McCoy said he heard gunshots before the explosion, which “blew everything all over the entire apartment.”“All the windows came in from the living room into the bedroom,” he told ABC News. “There was glass everywhere from the windows. There wasn’t really any part of the apartment that wasn’t damaged or pushed or moved or affected by the explosion … the whole apartment was just completely a mess.”“My building is pretty tall and pretty strong so it had to have been a very strong explosion to blow out all those windows,” he said.Several buildings suffered structural damage, authorities said.McCoy said he “started to go downstairs, saw some people in the hallway — they were in shock, you know, they’re crying.”He then reached the street which he said looked “like a movie … it was just surreal.”The debris field extends for at least a few blocks. Streets around the exploded vehicle have been closed down.In the search for the suspect, there are “investigate leads to be pursued” and “technical work that needs to happen,” the FBI said.“We will find out what happened here,” the FBI said.These are pictures from 2nd Avenue south. Windows were broken out from explosion area to Broadway. Please AVOID this area! Media staging is at 2nd Avenue south and KVB. pic.twitter.com/tocdpHWFgj— Nashville Fire Dept (@NashvilleFD) December 25, 2020Police have been sweeping the area with a K9 unit out of precaution, but Nashville Police Chief John Drake said there is no concern, and that “we know of no other imminent danger to the city at this point.”President Donald Trump, President-elect Joe Biden, acting Secretary of Homeland Security Chad Wolf, and acting Attorney General Jeff Rosen have been briefed on the incident.The FBI is now the lead investigative agency.Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives are responding.This story is developing. Please check back for more updates.Copyright © 2020, ABC Audio. All rights reserved.Nashville police officers were at first called to a report of shots fired. There was no evidence of shots fired but police noticed a suspicious RV with no tags parked across from the Davidson County courthouse.The bomb squad was called and around 6:30 a.m., as the bomb squad responded, the RV exploded, blowing out the windows of nearby buildings and leaving extensive damage.