The US Coast Guard said a remote-operated vehicle “reached the sea floor” and began searching for the missing Titanic submersible early Thursday morning — even though the officials believe the sub has likely run out of oxygen.

“The Canadian vessel Horizon Arctic has deployed an ROV that has reached the sea floor and began its search for the missing sub,” the agency said.

It added that “The French vessel L’Atalante is preparing their ROV to enter the water.”

The accelerating search efforts continued Thursday even as the sub likely ran out of oxygen, by officials’ calculations, at about 7:08 a.m.

When it took off Sunday, the sub carried 96 hours of oxygen for the crew of five, though experts have cautioned that their initial estimates may be inexact.

Rear Adm. John Mauger of the US Coast Guard told the TODAY Show the search efforts would continue at full force throughout the day as the Magellan “working class” remotely operated vehicle joins the search.

The vehicle, or ROV, has advanced capacities that include a manipulator arm capable of lifting a hull point to the surface of the water, NBC reported, citing a prior interview with Explorers Club President Richard Garriott, who criticized the Coast Guard for not utilizing the Magellan ROV sooner.

Responding to that criticism, Mauger noted: “We really had to start from scratch and bring all the capability that was available to bear on this problem.”

According to Mauger, officials decided to prioritize what was closest to the site.

“People’s will to live really needs to be accounted for as well, so we’re continuing to search and proceed with rescue efforts by bringing this new capability online this morning,” he said.

Those aboard the missing sub include Stockton Rush, the CEO of OceanGate who served as the vessel’s pilot, British billionaire Hamish Harding, Pakistani tech and energy mogul Shahzada Dawood and his 19-year-old son Sulaiman, and famed Titanic explorer Paul-Henri Nargeolet.

The Coast Guard said it received word from OceanGate about the missing submersible eight hours after it lost contact with its mothership, the Polar Prince.

The sub disappeared two hours after it submerged off the coast of Newfoundland on Sunday afternoon.

Unlike a normal submarine, a submersible is unable to get to the bottom of the ocean and back without its mothership. Meaning, without radio contact to the Polar Prince, the Titan will remain lost in the depths of the deep sea.