The Titan submersible's wreckage is thought to contain human remains, according to the US Coast Guard.
In St. John's, Canada, on Wednesday, pieces from the submarine that imploded while making a deep dive to the Titanic were unloaded.
The sub's landing frame and a rear cover, according to Coast Guard officials, were discovered among the debris.
The presumed remains will be subject to a formal analysis by US medical professionals, the coast guard announced in a statement.
The agency's investigation into what caused the Titan disaster is still in its early stages. The evidence will be transported to a US port by the Coast Guard's Marine Board of Investigation for additional investigation and testing.
In a statement released on Wednesday, MBI Chair Captain Jason Neubauer said, "I am grateful for the coordinated international and interagency support to recover and preserve this vital evidence at extreme offshore distances and depths.
According to him, there is still "a significant amount of work to be done to understand the factors that contributed to the catastrophic loss of the Titan and help ensure a similar tragedy does not occur again.".
On June 18, the ship imploded about 90 minutes into a dive to see the famous 1912 shipwreck, which is located at a depth of 3,800 meters (12,500 feet) in the north Atlantic. All five people on board perished.
The divers were Shahzada Dawood, 48, and his son Suleman Dawood, 19, as well as French diver Paul-Henry Nargeolet, 77. Stockton Rush, the head of OceanGate, which organized the dive, was 61.
Five significant pieces have so far been discovered in a sizable debris field close to the Titanic's bow, according to the Coast Guard.
According to BBC science correspondent Jonathan Amos, at least one titanium end cap, the sub's porthole with its window missing, a titanium ring, the landing frame, and the end equipment bay appeared to be among the debris that washed ashore on Wednesday.