UPDATE: Submersible likely imploded near Titanic, leaving no survivors, Coast Guard says
The U.S. Coast Guard says an underwater vessel has located a debris field near the Titanic in the search for a missing submersible with five people aboard, a potential breakthrough in an increasingly urgent around-the-clock effort.
The Coast Guard's post on Twitter gave no details, such as whether officials believe the debris is connected to the Titan, which was on an expedition to view the wreckage of the Titanic. The search passed the critical 96-hour mark Thursday morning when breathable air could have run out.
WATCH: More ships, equipment joining search for missing sub after reports of banging noises
The Titan was estimated to have about a four-day supply of breathable air when it launched Sunday morning in the North Atlantic — but experts have emphasized that was an imprecise approximation to begin with and could be extended if passengers have taken measures to conserve breathable air.