The Sincerity Ace, a 650-foot (198-meter) car carrier, had 21 crewmembers on board when the fire started Monday.
Ships in the area rescued 16 people. Four were listed as unresponsive in the water and the U.S. Coast Guard suspended its search for one crewmember listed as missing.
Japanese shipping company Shoei Kisen Kaisha Ltd. owns the Panamanian-flagged vessel.
Company spokesman Darrell Wilson says the vessel could still be on fire.
He says the tugboat is expected to arrive Sunday or Monday to tow the ship and try to recover bodies.