The "debris field", discovered by an underwater robot, has been identified from the missing Titanic submersible, an official statement from the US Coast Guard confirmed Thursday adding that the crew members onboard "have sadly been lost," as per OceanGate.

A debris field was discovered by a remotely operated vehicle on the ocean floor, roughly 500 meters off of the bow of the Titanic at about 8:55 a.m. Thursday.

The search for the five-member crew and the capsule of the Titan was continuing.

"We now believe that our CEO Stockton Rush, Shahzada Dawood and his son Suleman Dawood, Hamish Harding, and Paul-Henri Nargeolet, have sadly been lost," OceanGate said in a statement.

"Our hearts are with these five souls and every member of their families during this tragic time. We grieve the loss of life and joy they brought to everyone they knew. This is an extremely sad time for our dedicated employees who are exhausted and grieving deeply over this loss."

The debris was discovered after the search for the submersible passed the critical 96-hour mark when breathable air was expected to run out.

The submersible had about a four-day supply of breathable air when it launched Sunday morning in the North Atlantic.

Two more robots were deployed Thursday in the search for the Titan sub, lost somewhere in the North Atlantic between the ocean's surface and more than two miles (nearly four kilometers) below.

The 21-foot (6.5-meter) Titan began its descent at 8:00 am on Sunday and had been due to resurface seven hours later.

However, the craft lost communication with its mothership less than two hours into its trip to see the Titanic.

The Titanic's grave is situated 400 miles off the coast of Newfoundland in Canada, and more than two miles below the surface of the North Atlantic.