Search teams are racing against time to find a tourist submersible that went missing during a dive to the Titanic's wreck.

Five people were onboard when contact with the small sub was lost about an hour and 45 minutes into its dive.

As of Monday afternoon, it was thought the crew members had four days-worth of oxygen left at most.

One of those believed to be on board is British businessman and explorer Hamish Harding.

Two Pakistanis are also on the craft - businessman Shahzada Dawood and his son Suleman.

Stockton Rush, chief executive of OceanGate - the firm behind the dive - is also being widely reported to be on the vessel.

French explorer Paul-Henry Nargeolet is thought to be on board, according to a Facebook post by Mr Harding before the dive started.

The Titanic wreck is located about 600km (370 miles) off the coast of Newfoundland, Canada.