Rescuers race to find Titanic sub after hearing undersea sounds

A Canadian military surveillance aircraft detected underwater noises as a massive operation searched early Wednesday in a remote part of the North Atlantic for a submersible that vanished while taking five people down to the wreck of the Titanic.

A statement from the US Coast Guard did not elaborate on what rescuers believed the noises could be, though it offered a glimmer of hope for those lost aboard the Titan as estimates suggest as little as a day's worth of oxygen could be left if the vessel is still functioning.

Three vessels arrived on-scene Wednesday morning, including The John Cabot, which has side-scanning sonar capabilities and is conducting search patterns alongside two other vessels, the Skandi Vinland and the Atlantic Merlin, the Coast Guard tweeted.