Search and rescue teams were racing against time on Monday to find a tourist sub that went missing in the north Atlantic while on a dive to the wreck of the Titanic, writes The Guardian.

The US Coast Guard said “a small submarine with five persons onboard” had gone missing in the vicinity of the Titanic wreck and that the vessel had the capacity to be submerged for 96 hours, but it was unclear whether it was still underwater or had surfaced and was unable to communicate.

The submersible was reported overdue on Monday but contact was lost 1 hour 45 minutes into its dive on Sunday afternoon, the coast guard said.

A British explorer and a French military veteran and submarine expert were believed to be among those onboard the Titan, a deep diving submersible operated by underwater tourism company Oceangate.

Rear Admiral John Mauger, first district commander of the US coast guard, overseeing the search-and-rescue operation, told a press conference late on Monday afternoon that “we are doing everything we can do” to find the sub and its occupants.

US and Canadian ships and planes swarmed the area about 1,450km east of Cape Cod, some dropping sonar buoys that can monitor to a depth of almost 4,000m, the US Coast Guard said, but the search was “complex” because crews did not know if the vessel had surfaced, meaning they must scour both the surface and the ocean depths of nearly 13,000 feet.