The missing vessel is believed to be tour firm OceanGate's Titan submersible.

It weighs 23,000 lbs (10,432 kg), measures 6.7m (22ft) in length, and can hold five people for 96 hours.

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

Image source, .

Reports have emerged that Stockton Rush, the CEO and founder of OceanGate Expeditions – the company that organised the mission to the wreck of the Titanic – was on board the craft. 73-year-old Frenchman Paul-Henry Nargeolet was also reportedly on the submersible.

The BBC has not independently verified this information.

Two Pakistanis, Shahzada Dawood and his son Suleman, were also onboard the five-person expedition, according to a statement released by the family.

"We are very grateful for the concern being shown by our colleagues and friends and would like to request everyone to pray for their safety," the statement read.

Dawood is a trustee of the SETI Institute, a non-profit based on California, according to the organisation's website.

The search is taking place in a remote area, making operations complex and difficult.

The Titanic's wreck lies some 435 miles (700km) south of St John's, Newfoundland. US and Canadian ships have a vast area to cover in the search, as they scour the surface of the sea and as well as deep under the ocean.

• US and Canadian search teams are racing against the clock to find the tourist submarine with five people onboard
• The rescue operation continued overnight, but so far there has been no sign of vessel
• Military planes, a submarine and sonar buoys have been used
• Rear Adm John Mauger of the US Coast Guard said the focus was on getting as "as much capability into the area as we can"
• A research ship called the Polar Prince conducted a surface search for the sub on Monday evening, according to the US coastguard
• It is believed the crew members had at most roughly four days of oxygen left as of Monday evening

Nathan Williams
Live reporter

Hello and welcome as we resume our live coverage following the disappearance of a tourist sub in the mid-Atlantic.

US and Canadian search teams are racing against time to find the small sub that went missing during a dive to the wreck of the Titanic.

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

Titanic's wreck lies some 435 miles (700km) south of St John's, Newfoundland, though the rescue mission is being run from Boston, Massachusetts.

I'm here with my colleagues Charley Adams, Gabriela Pomeroy and Ali Abbas Ahmadi. Stick with us as we bring you the latest.

Brandon Livesay
Live reporter

With no further announcements expected from authorities for the rest of the day, we are pausing our live coverage of the missing submersible.

As it stands, there are five people aboard the missing vessel - which vanished during a dive to see the wreck of the Titanic.

• You can read more about the search and rescue operation in this article here
• And you can read about British adventurer Hamish Harding, who is believed to be among those onboard, in this article here

Our writers today have been Bernd Debussman Jr, Holly Honderich, Nathan Williams, Alys Davies and Ece Goksedef.

Thanks for joining us.

Image source, OCEANGATE

We've been following the search and rescue efforts underway in the North Atlantic, after a submersible went missing on Sunday morning - more than 24 hours ago.

Here's a quick look at what we know:

• The submersible has between 70-96 hours of emergency oxygen left (as of 17:00 local time)
• The submersible vanished in the ocean approximately 900 miles (1,448km) from Cape Cod, Massachusetts at a depth of roughly 13,000 feet (4km)
• Five people are on board. The Coast Guard said on Monday there is one pilot and "four mission operators," but did not elaborate further
• The US Coast Guard is working with Canadian forces and private vessels in the area
• The search involves sonar, aerial searches and surface vessels and is being carried out in a very remote location
• Part of the current operation involves anticipating what capabilities will be needed to rescue those aboard if found

The Coast Guard described sea conditions as "fairly normal" with three to six foot (1.82m) waves.

There is currently "low" visibility and fog in the area.

The weather in the area is, however, good enough for multiple aircraft to fly overheard.

Polar Prince, a vessel which transported the submersible to the site of the Titanic wreckage before the expedition, is now assisting with search and rescue efforts.

Carly Pickett, a spokesperson for Horizon Maritime, a co-owner of the ship, has confirmed its involvement to the BBC.

Polar Prince is a former Canadian Coast Guard icebreaking ship, Pickett said.

Horizon Maritime says it has also dispatched an additional vessel, the Horizon Arctic, to assist. The company’s website says the Horizon Arctic is “designed and equipped for advanced offshore support operations”.

The Canadian Coast Guard Ship Kopit Hopson 1752 has also been sent to help in the search and rescue operation.

Image source, Getty Images

The media update is over, but we have a few extra notes to bring you from what Rear Adm. Mauger had to say.

• The US Coast Guard is working with Canadian forces, who have deployed a C130 aircraft as well as a P8 Poseidon aircraft
• Part of the current planning is anticipating what capabilities will be necessary to rescue the submarine if it is found
• Mauger said the rescue teams "take this personally" and are doing everything they can to bring those onboard "home safe"
• The main focus is locating the missing submersible

Taking his final question, Rear Adm. John Mauger tells media that there is one pilot and "four mission operators" on board.

He tells the press conference the focus was on bringing these people home.

The roles of these mission operators is still not clear.

The missing submarine was designed with a 96 hour "emergency capability," Rear Adm. John Mauger tells media.

That means the vessel has 96 hours of oxygen in reserve if there is an emergency.

"We anticipate there is somewhere between 70 and the full 96 hours available at this point," Mauger says.

We're hearing now that the Coast Guard is working to bring additional capabilities on board to expand the search.

At the moment, Mauger said the Coast Guard's capabilities are "limited to listening to sounds", which means that additional resources will be necessary to search under the sea's surface.

Current efforts are completely focused on finding the vessel, and, if necessary, rescue capabilities.

Mauger has described the area in which the search is taking place as "remote", making operations difficult.

"Often times we rely on commercial operators to be the first vessels to be on scene," he said, adding that the US Coast Guard has been in touch with vessels in the area.

He added the search is made even more complex by the fact that the missing vessel may have not resurfaced, forcing the coast guard to use sonar to search under the sea's surface.

Rear Adm. John Mauger of the US Coast Guard says the force is doing everything it can do to "locate and rescue" those onboard the missing submersible.

The Coast Guard has been conducted a service search, as well as using aircraft of the area.

The Canadian Armed Forces is also deploying forces to the scene.

Robert Simpson, information officer USCG, is currently speaking and has again confirmed that five people are missing onboard the submarine.

We are expecting to hear from the US Coast Guard shortly at a news conference in Boston, US.

Stay with us for the latest.

Pallab Ghosh
Science correspondent

Dr Jamie Pringle, who is a reader in forensic geosciences at Keele University, says the ocean floor is a lot more rugged than on land - and there are different stratified levels of water.

“A typical land search for a missing person or vehicle would move outwards radially from the last known position. This is how this search is also likely being conducted.

“Techniques vary, but in that water depth, a sonar search system would need to be specialised to a very narrow beam but high enough frequency in order to resolve a small submersible”.

Malaysian Airlines flight MH370, which was lost in 2014 over the South China Sea, had a very large search radius and what happened to it still remains a mystery, Dr Pringle adds.

“This search should be a much smaller search radius, as the submersible was reportedly on a relatively simple down and up dive.”