A submarine taking tourists to the Titanic shipwreck has gone missing and the Coast Guard is searching for it

• A submarine that takes tourists to see the Titanic shipwreck has gone missing.
• The Boston Coastguard told the BBC a search was underway for the missing sub.
• It is unclear how many, if any, people were on board at the time it went missing.

A search mission is underway for a submarine that takes tourists to visit the Titanic shipwreck, the US Coast Guard based in Boston told told the BBC.

The sub went missing Monday.

The iconic shipwreck sits 12,500 feet at the bottom of the Atlantic Ocean, about 370 miles off the coast of Newfoundland, Canada. 

Tourists can pay to board small submersibles to explore what's left of the British passenger liner.

It is not clear how many people, if any, were on board at the time the vessel went missing, according to the BBC report.

The name of the company that runs the tour vessel was not yet identified.

Insider has reached out to the US Coast Guard for comment. 

This story is developing and will be updated.