The five people aboard a missing submersible are thought to be dead, according to the company that owns the vessel, bringing a grim end on Thursday to the massive search for the vessel that was lost during a voyage to the Titanic.

"These men were true explorers who shared a distinct spirit of adventure, and a deep passion for exploring and protecting the world’s oceans," OceanGate Expeditions said in a statement. "Our hearts are with these five souls and every member of their families during this tragic time."

The statement from OceanGate came just minutes after CNN said that debris found on the ocean floor on Thursday near the wreck of the Titanic was assessed to be from the submersible, citing an internal U.S. Coast Guard document.

(With input from Reuters)