Banging Sounds in 30-Minute Intervals Heard During Search for Missing 'Titan' Submersible: Report

While an internal email sent to the Department of Homeland Security does not share the cause of the sounds, another email reported the discovery of additional "acoustic feedback”

The ongoing search for a missing submersible carrying passengers to the underwater site of the Titanic continues as search and rescue discover new revelations.

In an internal email sent to the Department of Homeland Security leadership and obtained by Rolling Stone on Tuesday, the DHS shared that crews heard banging sounds in 30-minute intervals while searching where the sub's five passengers disappeared on Sunday morning.

Related: Everything to Know About the 'Titanic'-Bound Sub That Has Gone Missing

"RCC Halifax launched a P8, Poseidon, which has underwater detection capabilities from the air," the DHS email read, per Rolling Stone. "The P8 deployed sonobuoys, which reported a contact in a position close to the distress position. The P8 heard banging sounds in the area every 30 minutes. Four hours later additional sonar was deployed, and banging was still heard."

While the email does not share details of what might have caused the banging sounds, another email obtained by CNN reported the discovery of additional "acoustic feedback."

“Additional acoustic feedback was heard and will assist in vectoring surface assets and also indicating continued hope of survivors," said the email, according to CNN.

Related: Who Is on the Missing 'Titanic'-Bound Sub? All About the Passengers

News of the internal memos comes amid a press conference by U.S. Coast Guard Captain Jamie Frederick on Tuesday, where he announced that the submersible could have an estimated 40-41 hours of oxygen left of its 96-hour oxygen "reserve capacity."

The missing sub was part of OceanGate Expeditions, a company that hosts a “Titanic Expedition” to the historic site. Per their website, expeditions to the Titanic site began in the summer of 2023 and had a total of 18 dives planned.

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"Our entire focus is on the crewmembers in the submersible and their families," said OceanGate in a previous statement to PEOPLE. "We are deeply grateful for the urgent and extensive assistance we are receiving from multiple government agencies and deep-sea companies as we seek to reestablish contact with the submersible. We pray for the safe return of the crew and passengers."

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Read the original article on People.