The blaze at the Mariner's Cove Motor Inn was reported at about 5:30 am (GMT) today. The two-story wood structure was engulfed by flames when firefighters arrived.
Prosecutor Joseph Coronato says three males died in the fire and eight people were injured. Several of the injured sustained serious burns.
Coronato says the search and recovery phase of the investigation will continue until officials are certain they've accounted for the approximately 40 people who were registered at the motel.
The cause of the fire is under investigation.