Experts say they have recovered human remains from the debris.
"United States medical professionals will conduct a formal analysis of presumed human remains that have been carefully recovered," the agency said, having recovered and offloaded the mangled debris of the submersible.
The agency hopes to recover the remains of the five people on board the submersible, including British explorer Hamish Harding, French submarine expert Paul-Henri Nargeolet, Pakistani-British tycoon Shahzada Dawood and his son Suleman, and Stockton Rush, CEO of the sub's operator OceanGate Expeditions.
The five are presumed to have been killed instantly after the submersible imploded.
The leader of the US probe into the tragedy, Captain Jason Neubauer, said that they still have substantial work to do to understand the factors that led to the catastrophic loss of the Titan and help ensure "a similar tragedy does not occur again."
READ MORE: From Titanic To Titan: Death In Two Tragedies
Meanwhile, Pelagic Research, a New York-based company that owns and operates the robotic Odysseus deep sea vehicle used to search for Titan, said its offshore search-and-recovery operations have concluded.
They said that the debris was recovered from a depth of 1,600 feet on the ocean floor -- nearly four kilometres below the surface.
On June 18, Titan was reported as missing after losing contact with its mother ship.
READ MORE: What Happens During A Catastrophic Implosion?
Around four days later, authorities said all aboard were presumed dead based on a calculation of available oxygen on board.
The US Coast Guard's Marine Board of Investigation into the incident continues.