carlballou/iStockBy EMILY SHAPIRO, AARON KATERKSY, ABC NewsA parked recreational vehicle exploded in downtown Nashville, Tennessee, on Christmas morning, in what Nashville police believe was an “intentional act.”Crews are attempting to determine the cause of the explosion, which took place around 6:30 a.m., blowing out the windows of nearby buildings.Three people were transported. No significant injuries have been reported.The debris field extends for at least a few blocks. Streets around the exploded vehicle are being closed down.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.