Three heavyweight US congressmen jointly sent a letter to four tech giants on Monday (July 21), demanding Google, Meta, Microsoft, and Amazon to explain by a deadline whether their submarine telecommunications cable systems utilized equipment or services from Chinese companies. The legislators cautioned that China and Russia are infiltrating global infrastructure through a dual approach of “legal participation” alongside “illegal disruption,” posing a significant national security threat.
The letter was signed jointly by three chairmen of House committees, including Carlos Gimenez, Chairman of the Subcommittee on Transportation and Maritime Security of the Homeland Security Committee, John Moolenaar, Chairman of the Subcommittee on China of the Special Committee, and Keith Self, Chairman of the Subcommittee on Europe of the Foreign Affairs Committee.
They stated that these three congressional committees are responsible for overseeing whether foreign hostile forces are openly or covertly infiltrating and disrupting vulnerable links in these undersea cable systems.
In the letter (PDF), legislators pointed out that submarine telecommunications cables carry over 95% of global intercontinental data flow, not only supporting global commerce and innovation but also being vital to the backbone of US defense, intelligence, and national security communication systems.
The legislators questioned whether components produced, maintained, or integrated by Chinese or Russian affiliated entities were used in the submarine cable systems in which these companies are involved.
The explicitly named Chinese companies include Huawei Marine, China Telecom, China Unicom, and SB Submarine Systems. The legislators believe that if these entities continue to provide maintenance or services for submarine cable systems, sensitive infrastructure could be at risk.
The legislators noted that China and Russia are combining a strategy of “gray zone destruction” and “legitimate entry into supply chains.”
“Enterprises related to the Chinese Communist Party are also obtaining the rights to construct, maintain, and repair submarine cables ‘legitimately’ through commercial cooperation, multinational consortia, and state support investments. For instance, SB Submarine Systems, in which China Telecom holds shares, is a typical case of how the Chinese Communist Party embeds itself in critical infrastructure that could be monitored, disrupted, or controlled in the future,” the letter stated.
The legislators warned, “This dual strategy of engaging in gray zone destruction on the one hand and legitimate infiltration of supply chains on the other hand poses long-term risks to global communication, financial networks, and government and commercial service systems relying on cloud technology.”
The letter cited multiple cases to indicate that China and Russia are coordinating actions to conduct malicious activities against undersea infrastructure in the Baltic Sea, Indo-Pacific region, and other strategic areas.
“In the Baltic Sea, several damaging incidents have been traced back to commercial ships related to China and Russia, which intentionally drag anchors, shut down transponders, and have abnormal navigation tracks, conforming to the modus operandi of ‘gray zone operations,’ that is, exploiting legal gray areas to evade direct responsibility.”
The legislators cautioned that a similar pattern has emerged in the Indo-Pacific region. In 2023 and 2025, two major communication cables in the Taiwan’s Matsu region were disrupted by vessels operated by Chinese personnel, causing the island to lose connectivity with the global network. Additionally, three undersea cables in the Red Sea region were suspected of being sabotaged by Houthi militants, affecting major networks connecting Europe and Asia.
To prevent such infiltration, the Federal Communications Commission (FCC) in the US announced that it will vote on new regulations in early August, prohibiting any submarine cable systems using Chinese technology or equipment from landing in the US. Once passed, relevant companies will not be allowed to apply for construction, operation, or lease of such cable systems.
In the letter, the legislators listed seven specific questions, requiring the four companies to submit written responses by 5 p.m. on August 4 and to present briefings to the three committees by August 8.
The questions include whether the submarine systems involved use Chinese technology and equipment, whether there have been entities related to the Chinese Communist Party or Russian authorities participating in the construction or maintenance of the cables since 2018, whether abnormal signals or hardware tampering have been detected, what protective mechanisms are in place, and whether cooperation partners undergo national security reviews.
The legislators also want the tech companies to answer how they would monitor or respond if suspicious foreign vessels approach the cables, and whether they have received security briefings from US government agencies regarding threats from China and Russia, among other inquiries.