NASHVILLE, Tenn. (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 flights at the city’s airport.

Authorities said they believe the blast was intentional. Three people were hurt in the explosion, which shattered windows and damaged buildings.

Two law enforcement officials tell The Associated Press that authorities have found human remains in the vicinity of the explosion.

It was unclear how the remains were related to the explosion or whether they might belong to the person believed to be responsible or a victim. The officials spoke to the AP on condition of anonymity.