The US Navy detected sounds "consistent with an implosion" shortly after OceanGate's Titan submersible lost contact, a navy official has said.

Five people were aboard the vessel when it went missing during a dive to the Titanic wreck on Sunday.

The loss of the sub was confirmed after a huge search mission.

The official told CBS News their information about the "acoustic anomaly" had been used by the US Coast Guard to narrow the search area.

According to CNN, it was deemed to be "not definitive" and therefore the search and rescue mission continued.

Earlier on Thursday, Rear Adm Mauger of the Coast Guard confirmed that all five people aboard Titan had been killed following what was probably a "catastrophic implosion", based on patterns of debris discovered.

However, he said no sounds had been detected during the search mission that were consistent with this.

"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."

On Wednesday, the US Coast Guard confirmed that a Canadian P-3 aircraft had detected "underwater noises" in a search area for the missing vessel.

This brought new hope that the Titan's crew might be found alive and caused the Coast Guard to relocate operations.

According to CBS, those noises are now thought to have been coming from other ships in the area.

Paul Hankin, an undersea expert, said the first indication that the sub might have imploded came after a large debris field was found on Thursday.

"Essentially we found five different major pieces of debris that told us that it was the remains of the Titan," he said.

Efforts are continuing to map the debris field and to search the sea floor around the Titanic.

Contact with the vessel was lost about an hour and 45 minutes into its dive nearly a week ago. Titanic's wreck lies some 435 miles (700km) south of St John's, Newfoundland.

Aboard the vessel was British billionaire businessman Hamish Harding, who had written on social media ahead of the dive that it was taking place because a "weather window" had opened up,

He said that because of the "worst winter in Newfoundland in 40 years" the mission was "likely to be the first and only manned mission to the Titanic in 2023".

British father and son Shahzada and Suleman Dawood were also part of the crew. They were from one of Pakistan's richest families.

OceanGate CEO Stockton Rush also died on Titan, alongside former French navy diver Paul-Henry Nargeolet.