A distress signal was sent from the missing Titanic submarine as the race against time to rescue the five people on board continues.
Five people, including a British billionaire and father and son living in Surrey, crewed a submersible that delved nearly 4000m under the sea to visit the Titanic wreck.
But things took a distressing turn for the worse when contact with the sub was lost just 15 minutes from the famous ship's last resting place.
US Coast Guard have been leading a desperate search to try and locate the submarine amid concerns passengers only have enough oxygen to last until around midday Thursday.
But oceanologist Dr Simon Boxall, of the University of Southampton, said a distress signal was sent out by the submarine.
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However, he didn’t know when the ping was sent out, and if it was automatic, or done by the crew members.
Dr Boxall said: "This is second-hand knowledge but my understanding is that they have received a signal from the submarine.
"You can't use radios underwater. You rely totally on 'pings'. What they have is really limited communication.
"Apparently they have had, and I don't know when ... they have had an emergency ping saying the vessel is in distress.
“I don't know if that is automatically generated or generated by people on board.
"It could be that the vessel is lost already or it could be automatic."
He added he didn’t know when the ping was transmitted.
This comes amid growing concern for the safety of the crew on board as rescue efforts continue.
British billionaire Hamish Harding, father and son duo Shahzada Dawood, 48, and Sulaiman Dawood, 19, French Navy veteran Paul-Henry Nargeolet, and OceanGate CEO Stockton Rush - the company behind the submarine expedition - were all on board.
This morning, the UK Ministry of Defence indicated that NATO’s submarine rescue system (NSRS) might not be able to reach the vessel - even if it’s located.
This is because the “depths of water involved greatly exceed” those which the NATO sub can operate on.
An NSRS submersible can only operate at 610 metres and when operated remotely can go down to around 1,000 metres.
The Titanic wreck is almost 4,000 metres underwater.
The OceanGate Titan sub launched around 4am Sunday, and its last ping occurred one hour and 45 minutes into what was supposed to be a two hour descent to the Titanic.
There is now concern from some that the rescue operation isn’t moving fast enough.
David Concannon, an attorney and explorer who pulled out of the trip at the last minute, has slammed the US government for holding up rescue efforts due to paperwork.
He said the group that did the advanced survey of the Titanic last year has been sat on the tarmac in the Guernsey Islands, waiting for authorisation to move.
Despite the fact there’s a ship ready to take them to the site, Mr Concannon said it was “unacceptable” how slow the US authorities were moving.
He told NewsNation: “We need to move. We do not have minutes or hours. We need to move now.
“We have people whose lives are at stake. You have to move. We have assets that are ready to go and they’re sitting and waiting.”
