According to the USGC, a Canadian P-3 aircraft detected the sounds in the search area, prompting authorities to relocate their search.
The BBC, citing US media, described the noises as "banging sounds" heard in 30-minute intervals.
Contact with the miniature sub, which is carrying five people, was lost on Sunday (18 June) as it made a 3,800m descent to the wreck of the RMS Titanic.
British billionaire business executive and explorer Hamish Harding, 58, chair of aircraft firm Action Aviation, is among those trapped on the craft, his family confirmed on Monday (19 June).
Also onboard is British-Pakistani businessman Shahzada Dawood and his son Suleman, as is former French navy diver Paul-Henry Nargeolet and chief executive of OceanGate – the firm behind the dive – Stockton Rush.
According to earlier US Coast Guard estimates, as of Wednesday morning (21 June), the Titan has less than 30 hours of oxygen remaining onboard.
