Five people who were on a sub that went missing during a voyage to the wreckage of the Titanic did not survive, the company that planned the trip said Thursday, as the U.S. Coast Guard said the OceanGate vessel experienced a "catastrophic loss of the pressure chamber," and confirmed that the debris found on the sea floor were pieces of the missing sub.

"This is a incredibly unforgiving environment down there on the sea floor and the debris is consistent with a catastrophic implosion of the vessel," Coast Guard Rear Adm. John Mauger told reporters.

A U.S. Navy official said the Navy detected "an acoustic anomaly consistent with an implosion" shortly after the sub, named Titan, lost contact with the surface Sunday, CBS News national security correspondent David Martin reported. The information was relayed to the Coast Guard, which used it to narrow the radius of the search area, the official said.

Meanwhile, banging noises that were detected during the week were assessed to have been noise from other ships in the area, Martin reported.

On Thursday morning, an ROV, or remotely operated vehicle, from a Canadian vessel found the tail cone of the sub about 1,600 feet from the bow of the Titanic, Mauger said during a briefing in Boston on Thursday afternoon. He said more debris was found and authorities consulted with experts who determined the debris found over 2 miles beneath the water's surface was consistent with the sub.

"On behalf of the United States Coast Guard and the entire unified command, I offer my deepest condolences to the families," Mauger said. "I can only imagine what this has been like for them, and I hope that this discovery provides some solace during this difficult time."

Pakistani businessman Shahzada Dawood, his 19-year-old son Suleman, billionaire adventurer Hamish Harding, French explorer Paul-Henri Nargeolet and OceanGate founder Stockton Rush were on the sub.

Paul Hankins, a U.S. Navy salvage expert, said at the briefing that the sub was found scattered in pieces, and that the team "will do the best we can to fully map out what's down there."

"Essentially 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," he said. "We then found a large debris field" followed by "a second, smaller debris field."

Carl Hartsfield of the Woods Hole Oceanographic Institution said the sub's wreck was found in a smooth area of the sea floor where there wasn't any debris from the ocean liner that sank on its maiden voyage in 1912.

Mauger said it was too early to tell when the sub imploded.

"We know that — as we've been prosecuting this search over the course of the last 72 hours and beyond — that we've had sonar buoys in the water nearly continuously and have not detected any catastrophic events when those sonar buoys have been in the water," he said.

The sub launched into the Atlantic from a Canadian research vessel Sunday morning, and the ship lost contact with the Titan an hour and 45 minutes into the dive.

"I know that there's also a lot of questions about how, why and when did this happen, and so, you know, those are questions that we will collect as much information as we can on now while the governments are meeting and discussing what an investigation of this nature of a casualty might look like," Mauger said. "...I'm confident that those questions will begin to get answered."

Underwater robots will remain at the search site to gather additional information about the sub, Mauger said. Another robot from a French vessel was also launched into the water Thursday.

"This was a incredibly complex case, and we're still working to develop the details for the timeline involved with this casualty and the response," he said.

Asked about the prospects for recovering the remains of the deceased, Mauger said, "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."

"Our thoughts are with the families and making sure that they have an understanding as best as we can provide of what happened and begin to find some closure," he said.

Harding's family and his company said in a statement that the adventurer was "one of a kind and we adored him."

"What he achieved in his lifetime was truly remarkable and if we can take any small consolation from this tragedy, it's that we lost him doing what he loved," the statement said. "He will leave a gap in our lives that can never be filled."

Explorers Club president Richard Garriott de Cayeux said in a statement that Harding and Nargeolet "were both drawn to explore, like so many of us, and did so in the name of meaningful science for the betterment of mankind."

The Dawood family said they were experiencing an "unimaginable loss" and thanked search crews.

"Their untiring efforts were a source of strength for us during this time," the family said in a statement.

Thursday's news followed a massive international search effort for the lost 21-foot sub.

In addition to the robots, search planes and ships have been deployed to the northern Atlantic Ocean in the hopes of finding the sub approximately 900 nautical miles from Cape Cod, Massachusetts. The Coast Guard said Wednesday the search area was about twice the size of Connecticut.

Officials previously said the sub had a limited amount of oxygen on board that could have lasted 96 hours, or roughly until Thursday morning.

In:
• RMS Titanic
• United States Coast Guard

Alex Sundby

Alex Sundby is a senior editor for CBSNews.com

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