A submersible used to take tourists to the wreck of the Titanic has vanished in the Atlantic Ocean.
The sudden disappearance has sparked a search and rescue operation, the Boston Coastguard told the BBC.
It is not yet known how many people were on board the missing craft.
The Titanic wreck lies 3,800 metres down at the bottom of the Atlantic, 400 nautical miles off the coast of Canada.
It sunk in April 1912 after striking an iceberg on its maiden voyage.
The wreck was discovered in 1985.
In recent years, small submersibles have started taking tourists to visit the craft. One company charges €250,000 per passenger.
This breaking news story will be updated as more details emerge.