The Boston Coastguard told BBC News that a search and rescue operation was under way off the coast of Newfoundland.
It is unclear how many people were on board when it went missing.
Small submersibles occasionally take paying tourists and experts to view the wreck of the Titanic, some 3,800m (12,500ft) beneath the ocean surface.
OceanGate Expeditions, a private company that organises deep sea expeditions, confirmed in a statement that it owned the missing submersible and people were on board.
“We are exploring and mobilising all options to bring the crew back safely,” it said on Monday. “Our entire focus is on the crewmembers in the submersible and their families.”
“We are working toward the safe return of the crewmembers,” it added.
The company charges guests $250,000 (£195,270) for a place on its eight-day expedition to see the famous wreck.
It bills the trip on its carbon-fibre submersible as a “chance to step outside of everyday life and discover something truly extraordinary”.
According to its website, one expedition is ongoing and two more have been planned for June 2024.
Full Story: https://www.bbc.com/news/world-us-canada-65953872
