The head of the Titanic submersible rescue mission has revealed that search crews are concentrating on "banging" noises detected on sonar - which could indicate there is a chance of "survival".
Rear Admiral John Mauger, from the US Coast Guard, said his team "don't know" the source of the noise but have passed on their data to the US navy. The sounds was picked up by a Canadian P-3 aircraft and underwater operations are being carried out in order to pinpoint their origin, the Mirror reports.
According to the US Coast Guard, the noises were identified in the area that is currently being searched for the missing submersible. The vessel - which is owned and run by OceanGate Expeditions - lost communication less than two hours into its journey to the Titanic wreckage site on Sunday.
Mr Mauger said in a press conference there a lot of metal objects at the site, which is why it's essential to find navy experts who consider the science behind the noise.
He added: "The data from the P-3 aircraft has been shared with our U.S. Navy experts for further analysis which will be considered in future search plans.
"There is a lot of metal and different objects in the water around this site. That’s why it’s so important that we’ve engaged experts from the Navy that understand the science behind noise and can classify or give us better information about what the source of that noise may be."
He added that the search is "incredibly complex" and that multiple different agencies are working to find the submarine before the oxygen runs out on Thursday morning. Coast Guard Captain Jamie Frederick told reporters on Tuesday the passengers had "about 40 hours of breathable air left" - an estimation based off the vessel's original 96 hours of available oxygen.
He said: "We will do everything in our power to effect a rescue. There is a full-court press effort to get equipment on scene as quickly as we can."
Captain Frederick added that authorities will continue to look for the source of the noise "as long as there's an opportunity for survival" and said the noise is "a target, it's a focus for us to look at", with vessels being deployed nearby. So far, underwater operations have yet to find any other trace of the missing sub, according to Richard Garriott de Cayeux, the president of the Explorers Club.
In a letter to club members, Richard said: "There is cause for hope, based on data from the field - we understand that likely signs of life have been detected at the site."
One of the passengers on board, British businessman Hamish Harding, helped found the club's board of trustees. Pakistani British-based businessman Shahzada Dawood and his 19-year-old son, Sulaiman Dawood, are also onboard alongside French submersible pilot Paul-Henry Nargeolet, and chief executive and founder of OceanGate Expeditions, Stockton Rush.
So far, the US Navy and Air National Guard have searched a combined area of around 7,600 square miles, which is larger than the state of Connecticut.
Don't miss the latest news from around Scotland and beyond - Sign up to our daily newsletter here .
