BOSTON: A desperate air and sea rescue effort to find the tourist submersible that went missing near the wreck of the Titanic quickened Tuesday, with officials warning that the five people on board had less than two days of oxygen left.

All communication was lost with the 21-foot (6.5-meter) craft during its descent Sunday to the wreck of the Titanic, which sits more than two miles (nearly four kilometers) below the surface of the North Atlantic.

The submersible, named Titan, was carrying three fee-paying passengers: British billionaire Hamish Harding, Pakistani tycoon Shahzada Dawood and Dawood’s son Suleman. OceanGate Expeditions, which runs the Titan’s trips, charges $250,000 for a seat.

Ships, planes search for sub that went missing on trip to Titanic wreckage

The US and Canadian Coast Guards have deployed ships and planes in an intensive search for the vessel, which was attempting to dive near the Titanic some 400 miles off the coast of Newfoundland, Canada.

“There’s about 40 hours of breathable air left based on that initial report,” he said around 1:00 pm (1700 GMT).