A submersible used to take tourists to view the wreck of the Titanic has gone missing in the Atlantic Ocean, sparking a search and rescue mission.
The Boston Coastguard told the BBC an operation to find the submersible was underway on Monday.
It is not clear how many people, if any, were on board at the time it went missing.
Small submersibles occasionally take paying tourists to view the wreck of the Titanic which can cost upwards from about $125,000.
The famous shipwreck sits 3,800m (12,500ft) down at the bottom of the Atlantic. It is about 600km (370 miles) off the coast of Newfoundland, Canada.
The passenger liner, which was the largest ship of its time, hit an iceberg on its maiden voyage from Southampton to New York in 1912. Of the 2,200 passengers and crew on board, more than 1,500 died.
The Titanic has been extensively explored since the wreck was discovered in 1985.
This breaking news story is being updated and more details will be published shortly.