A massive search is currently underway in the mid-Atlantic after a tourist submarine went missing after it dived to reach the wreck of the iconic Titanic.

Contact with the small sub was lost about an hour and 45 minutes into its dive, the US Coast Guard was quoted as saying by BBC.

Tour firm OceanGate said: "We are working toward the safe return of the crew members."

US Coast Guard also issued a statement on the development and said: "The Coast Guard is searching for five persons after the Canadian research vessel Polar Prince lost contact with their submersible during a dive, approximately 900 miles east of Cape Cod, Sunday morning."

"A Coast Guard Air Station Elizabeth City, North Carolina, C-130 Hercules aircraft, as well as a Canadian P8 aircraft equipped with underwater sonar capability, are currently searching for the missing submersible," read the statement.

Tickets cost $250,000 (£195,000) for an eight-day trip including dives to the wreck at a depth of 3,800m (12,500ft), reports BBC.

Government agencies, the US and Canadian navies and commercial deep-sea firms are reportedly helping the rescue operation.