Explosion in downtown Nashville

A vehicle on fire after the Christmas Day explosion. Buildings shook in the immediate area and beyond after a loud boom was heard. (Andrew Nelles/The Tennessean via AP)

NASHVILLE, Tennessee (AP): A recreational vehicle parked in the deserted streets of downtown Nashville exploded early Christmas morning, causing widespread communications outages that took down police emergency systems and grounded holiday travel at the city's airport.

Authorities said they believe the blast was intentional.