A submarine used to take tourists to the famous Titanic shipwreck in the Atlantic Ocean has gone missing amid a major search and rescue operation.

The Boston Coastguard said that it was now looking for the missing vessel off the coast of Newfoundland.

It is not known how many people were on board at the time of the disappearance.

The small submarine was occasionally used to take paying tourists and experts to view the wreck of the passenger liner which was sunk by an iceberg in 1912.

The White Star Line ship was sailing from Southhampton to New York and carried some 3,547 crew and passengers after being constructed in Belfast.

The Titanic site is around 3,800m beneath the ocean surface with OceanGate Expedition charging guests $250,000 (£195,270) for a place on the sought-after eight-day trip.

The deep-sea company has yet to comment on reports or confirm that any of its submersibles are missing.

The BBC reported that the company's website dubs the trips as a "chance to step outside of everyday life and discover something truly extraordinary".

The company's site also said that one of its trips is ongoing with two more planned in June 2024.

These submarines can seat five people according to the company which is said to include the pilot, three paying customers and a 'content expert'.

The trips also include a full dive which is said to take around eight hours.

The site where the Titanic sank was discovered in 1985 and has been explored and excavated extensively since then.

This comes after a full-size digital scan was carried out of the wreck using deep-sea mapping technology.

This was able to show the size and scale of the ship as well as some other details like the serial number of one of the propellers.