The US Coast Guard was searching for a Canadian passenger who jumped off a Royal Caribbean Cruises ship as it motored off a remote Puerto Rican island toward the US territory's mainland.
During a statement on Sunday, the Coast Guard identified the missing man as Tien Phuoc Nguyen, a 26-year-old Canadian citizen who was on the final night of a seven-night Caribbean cruise with his family.
Mr Nguyen was last seen jumping overboard by other passengers late on Saturday, as the Adventures of the Sea was transiting east of Mona Island, an uninhabited land mass in a rough sea passage between Puerto Rico and the Dominican Republic.
Royal Caribbean spokeswoman Cynthia Martinez said on Sunday that the captain immediately stopped the cruise ship, turned around and alerted local authorities after a passenger reported seeing a man going overboard late Saturday.
In a Sunday email, Martinez said footage of the incident was also captured by the ship's cameras.
The Coast Guard deployed helicopters and a patrol boat but there has so far been no sign of the missing passenger.
The FBI is investigating the circumstances which may have led Mr Nguyen to jump overboard.
When the U.S. Coast Guard assumed control of the search early Sunday, the cruise ship resumed its trip to Puerto Rico's capital of San Juan. Martinez said that a Royal Caribbean team was providing support to Mr Nguyen's family.
The Royal Caribbean ship was finishing its seven-night trip and returning to San Juan when he jumped overboard.
Additional reporting by Associated Press