All five onboard the missing Titan sub are believed to have died, the company that operates the submersible said in a statement.

“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,” an OceanGate statement 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.”

US Coast Guard makes statement – live updates

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1:33

‘Two friends of mine are gone’

In a news conference minutes later, Rear Admiral John Mauger – who is leading the search – confirmed that a remotely operated vehicle had discovered the tail cone of the missing sub, approximately 1,600ft from the bow of the Titanic on the seafloor.

Additional debris was found nearby, with Mr Mauger adding: “In consultation with experts from within unified command, the debris is consistent with the catastrophic loss of the pressure chamber.

“On behalf of US Coast Guard and entire unified command, I offer deepest condolences to the families. I can only imagine what this has been like for them, and I hope this discovery provides some solace during this difficult time.”

Sky’s US correspondent, James Matthews, asked the rear admiral whether any trace of the five passengers had been found.

Mr Mauger replied: “This is an incredibly complex operating environment on the seafloor, over two miles beneath the surface. The remote operating vehicle has been searching, and it s highly capable, and we’ve been able to classify parts of the pressure chamber for the Titan submersible.”

When asked about the prospects for recovering crew members, Mr Mauger warned “it is an incredibly unforgiving environment on the seafloor”.

While the debris is consistent with a “catastrophic implosion” of the vessel, he stressed that it is too early to know when this happened.

“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,” he told reporters.

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1:12

‘Why were you worried about Titan?’

An expert later added that no debris from the Titanic is based in the area – and underwater robots remain on scene to gather information.

While there had been speculation in past news conferences that underwater banging noises heard near the site could be linked to Titan, the Coast Guard said there doesn’t appear to be a connection.

Early on Thursday morning, it had been confirmed that a “debris field” had been found at the search site.

A rescue expert who knows two of the five men onboard had told Sky News that Titan’s landing frame and rear cover had been identified.

Five days have passed since Titan’s passengers embarked on a two-hour dive to see the wreck of the Titanic – and teams from multiple countries have scoured thousands of square miles looking for the minivan-sized vessel.

On Wednesday, the US Coast Guard had forecast that the vessel’s air supply would run out by 12.08pm UK time today.

Finding the missing submersible in a totally dark environment was likened to discovering a needle in a haystack – and according to experts, even specialist vehicles on the seafloor can only see for a matter of metres.