The pilot and four passengers of the missing Titan submersible are believed to be dead.

OceanGate Expeditions said its pilot and chief executive Stockton Rush – along with UK citizens Hamish Harding, Shahzada Dawood and his 19-year-old son Suleman Dawood and French national Paul-Henri Nargeolet “have sadly been lost.”

The US Coast Guard offered its “deepest condolences” to the families after the tail cone of the submersible was found around 1,600ft from the bow of the Titanic wreckage.

In a press conference, Rear Admiral John Mauger said further debris was “consistent with a catastrophic loss of the pressure chamber”.

In a statement, OceanGate Expeditions said: “These men were true explorers who shared a distinct spirit of adventure, and a deep passion for exploring and protecting the world’s oceans.

“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.”

At the press conference in Boston, Rear Admiral Mauger said: “This morning, an ROV, or remote operated vehicle from the vessel Horizon Arctic discovered the tail cone of the Titan submersible approximately 1,600ft from the bow of the Titanic on the sea floor.

“The ROV subsequently found additional debris. In consultation with experts from within the unified command, the debris is consistent with the catastrophic loss of the pressure chamber.

“Upon this determination, we immediately notified the families.

“On behalf of the United States Coast Guard and the entire unified command, I offer my deepest condolences to the families. I can only imagine what this has been like for them.

“And I hope that this discovery provides some solace during this difficult time.”

Asked what the prospects of recovering crew members were, Rear Admiral Mauger said: “This is an incredibly unforgiving environment down there on the sea floor and the debris is consistent with a catastrophic implosion of the vessel.

“And so we’ll continue to work and continue to search the area down there, but I don’t have an answer for prospects at this time.”

We found five different major pieces of debris that told us that it was the remains of the Titan

Rear Admiral Mauger said there did not appear to be any connection between the underwater noises detected during the search and rescue mission and the location of the debris on the seafloor.

“This was a catastrophic implosion of the vessel which would have generated a significant broadband sound down there that the sonar buoys would have picked up,” he said.

Undersea expert Paul Hankin said five major pieces of debris helped to identify it as from the Titan submersible.

He told reporters: “We found five different major pieces of debris that told us that it was the remains of the Titan.

“The initial thing we found was the nose cone which was outside of the pressure hull.

“We then found a large debris field. Within that debris field we found the front end bell of the pressure hull.

“That was the first indication that there was a catastrophic event.”

He continued: “Shortly thereafter we found a second smaller debris field. Within that debris field we found the other end of the pressure hull.

“We continue to map out the debris field, and as the admiral said, we will do the best we can to fully map out what’s down there.”

Foreign Secretary James Cleverly described the update as “tragic news” and said the UK Government is closely supporting the British families affected.

Pakistan’s Foreign Ministry offered its “deepest condolences” to the Dawood family and the families of other passengers.

In a Twitter post, a spokesman said: “We appreciate the multi-national efforts over the last several days in search of the vessel.”