A submersible known for taking tourists into the deep sea to view the Titanic wreckage has gone missing in the Atlantic Ocean.

The U.S. Coast Guard is working with Canada's coast guard and armed forces to search for the 21-foot vessel that lost communication with its control center.

"The 5 person crew submerged Sunday morning, and the crew of Polar Prince lost contact with them approximately 1 hour and 45 minutes into the vessel's dive," the U.S. Coast Guard Northeast wrote on Twitter.

At a press conference on Monday, Rear Admiral John Mauger of the U.S. Coast Guard said search and rescue teams are using aircrafts to scan the ocean, as well as sonar devices to detect possible underwater sounds coming from the submersible.

Mauger did not disclose the identities of the people on board but confirmed that officials are in process of notifying the passengers' families.

The vessel lost communications at about 435 miles (380 nautical miles) south of St. John's, Newfoundland, Canada's Joint Rescue Coordination Centre in Halifax, Nova Scotia, said on Twitter.

The missing vessel is owned by OceanGate, a company based in Washington state that offers underwater voyages to explore the remains of the iconic shipwreck from the seafloor.

"We are exploring and mobilizing all options to bring the crew back safely," the company said in a statement.

Its vessels are "equipped with some basic emergency medical supplies and 96 hours of life support," according to the company's website via the Wayback Machine. It takes approximately 2.5 hours to return back to the surface from the seabed, according to OceanGate.

The National Oceanic and Atmospheric Administration told NPR that it is also aware of the missing submersible and is closely monitoring the situation.

The company's deep sea tour lasts about eight days and costs $250,000 per person. From St. John's in Newfoundland, Canada, explorers travel 380 miles offshore and 2.3 miles below the surface, according to the company's website.

The company gained popularity in recent years for its expeditions to the Titanic, and most recently the group created the first-ever-full-sized digital scan of the shipwreck.
Not the first time an OceanGate submersible was lost

This is not the first time an OceanGate submersible has gone lost, according to David Pogue, a correspondent for CBS Sunday Morning.

Pogue, who traveled on an OceanGate expedition to see the Titanic last summer, recalled that the control room was unable to help the submersible locate the wrecked liner for roughly three hours due to technical difficulties.

"The difference this year is that it seems like they lost contact with the ship," Pogue told NPR. "They can't even reach the sub and that's really scary."

The deep sea is difficult to navigate because there is no GPS or radio signals underwater, according to Pogue. The submersible relies on directions sent by the control center.

"All of these submersibles have been kind of janky," Pogue said.

He added that factors like bad weather and mechanical issues can hinder the expedition. In fact, the vessels rarely make it to the Titanic, despite the expensive price tag, according to Pogue.