The officials became concerned when a state-controlled Chinese firm that repairs undersea cables, SB Submarine Systems, unexplainably and repeatedly concealed the location data of its ship from radio and satellite tracking services. They said the ship's concealment of its position "defied easy explanation."

The warnings about potential espionage or even sabotage of undersea cables come nearly three months after underwater telecommunications cables linking Europe and Asia were "damaged" in the Red Sea between Jeddah in Saudi Arabia and Djibouti in East Africa. 

We were the first to report a mysterious Iranian spy ship was operating near the incident area. At the time, David Asher, a senior fellow at Hudson Institute, said, "The Qods Force is operating a spy ship called the 'Behsad' that is reportedly in the Gulf of Aden, not far from where the undersea cables were cut. This ship highly likely carries a Qods Force special underwater warfare force component more than capable of carrying out an undersea cable attack."

A US defense official recently warned Silicon Valley giants such as Google and Meta Platforms about the mounting risks the Chinese could threaten US-owned cables: 

US officials have told companies, including Google and Meta, about their concerns that Chinese companies could threaten the security of US-owned cables, a person familiar with the briefings said. In some cases, the conversations have included discussion of Shanghai-based SB Submarine Systems, the person said. -WSJ

WSJ provided more color on the Chinese maintenance firm that repairs broken internet lines: 

Senior Biden administration officials have also received briefings in recent months about the risks posed by Chinese companies, including SBSS, working on repairs to undersea cables, according to the person.

The security of undersea cables "is rooted in the ability of trusted entities to build, maintain, and repair" them "in a transparent and safe manner," the National Security Council said in a statement, noting that satellite ship tracking "is one such measure that supports vessel monitoring and safety."

Digging deeper into SBSS, data from Sayari, a top counterparty and supply chain risk intelligence provider, shows a web of connections the company has, including several major risk factors.