A Chinese research vessel loitering near an undersea cable ignored demands by the Philippine Coast Guard to withdraw, broadcasting a false identification and taking evasive action, according to a report by Nikkei Asia. The September incident prompted the Philippines to dispatch its largest vessel, while a Chinese coastguard ship intervened and Beijing complained of harassment. The article says several incidents suggest China is actively mapping the seafloor for vulnerabilities.
Undersea cables carry the vast majority of the world’s internet traffic, making them a strategic asset. Chinese operations near cables in the South China Sea have drawn increasing attention from U.S. think tanks and Congress, who warn that Beijing may be preparing to disrupt communications in a crisis.
The Philippine Coast Guard responded to a Chinese vessel near an undersea cable. The ship reportedly ignored radio contact and broadcast a false identification before maneuvering to evade capture. The Philippines sent its largest vessel, which was spotted 37 nautical miles from Batanes province, officially part of the Philippines but claimed by China. A Chinese coastguard ship intervened. Beijing later complained of harassment, the South China Morning Post reported.
A report from the Center for Strategic and International Studies, a Washington-based think tank, found that Chinese research ships spend more time loitering near undersea cables than those of any other nation, describing the efforts as “disproportionate.” A U.S. congressional report from 2025 highlighted that China is actively developing techniques to cut cables and that Chinese research teams had publicly disclosed details of electric cutting devices capable of severing armored cables as deep as 13,000 feet underwater.
Ryan Claffey, a research assistant for the Center for a New American Security, warned in a report that “subsea cables are digital lifelines” and argued that “the U.S. and its allies must protect them in peacetime to stay connected in crisis.”
Russia has used fishing trawlers for nearly five years to loiter over communication cables in Europe, and Iran has threatened to attack undersea cables in the Strait of Hormuz if the United States attacks it again, describing them as legitimate targets during war.
Analysis
Why This Matters
- Undersea cables carry the vast majority of global internet traffic; any disruption could have severe economic and communications impacts.
- The incident suggests China may be preparing to disrupt this infrastructure in a conflict, escalating gray-zone operations in the region.
- The Philippine response and Beijing’s complaint indicate rising tensions that could lead to direct confrontation.
Background
China has long-standing maritime disputes in the South China Sea with the Philippines, Vietnam, Malaysia, Brunei, and claims over Taiwan. Beijing claims the area as its territory. In recent years, Chinese civilian research vessels have been increasingly active near undersea cables, raising concerns about mapping and potential sabotage. Similar operations by Russia and Iran have been observed in other regions.
Key Perspectives
Philippine Coast Guard: Demanded the Chinese vessel withdraw after it was spotted near an undersea cable and sent its largest vessel in response.
Beijing: Complained of harassment after a Chinese coastguard vessel intervened.
Ryan Claffey (Center for a New American Security): Called for a coordinated U.S. and allied response, arguing that subsea cables are “digital lifelines” that must be protected.
U.S. Congressional Report (2025): Highlighted that China has developed techniques to cut cables, including electric cutting devices at great depths.
What to Watch
- Whether further incidents occur near undersea cables in the South China Sea.
- The response from the U.S. and its allies, including possible joint patrols or protective measures.
- Any diplomatic fallout between China and the Philippines over the incident.
Checked
12 claims in this story checked against 1 source: 9 supported.
Show each claim
- SupportedThe headline says a Chinese research vessel ignored Philippine demands near an undersea cable and took evasive action.Latest from Tom's Hardware: “Chinese survey ship loitering near undersea cable ignores Philippine demands to withdraw — evasive action point to growing PRC threats to data lines in the Pacific.”
- SupportedThe summary characterises Chinese cable loitering as “gray-zone” warfare.Latest from Tom's Hardware: “China is loitering over undersea cables in “gray-zone” warfare against neighboring countries, as well as the U.S. and its allies”
- SupportedThe Philippine Coast Guard’s demands to withdraw were ignored.Latest from Tom's Hardware: “Chinese survey ship loitering near undersea cable ignores Philippine demands to withdraw”
- SupportedThe vessel broadcast a false identification.Latest from Tom's Hardware: “The vessel reportedly ignored radio contact while broadcasting a false ID”
- SupportedThe vessel manoeuvred to evade capture.Latest from Tom's Hardware: “before manoeuvring to evade capture.”
- SupportedThe Philippines sent its largest vessel in response.Latest from Tom's Hardware: “The Philippines, in response, sent its largest vessel to respond.”
- SupportedThe Philippine vessel was spotted 37 nautical miles from Batanes, which the source says is officially part of the Philippines but claimed by China.Latest from Tom's Hardware: “That vessel was spotted 37 nautical miles away from the Batanes province, officially part of the Philippines but claimed by China.”
- Not in the sourcesUndersea cables carry the vast majority of the world’s internet traffic.Latest from Tom's Hardware: “Ryan Claffey, a research assistant for the Center for a New American Security, a thinktank that specializes in U.S. national security, believes that a coordinated response is required to stop Chinese actions in the region.”
- Not in the sourcesChinese operations near cables have drawn increasing attention from U.S. think tanks and Congress.Latest from Tom's Hardware: “A report by the Center for Strategic and International Studies, a U.S.-based think tank in Washington, DC, found that Chinese research ships were spending more time loitering near cables than any other nation.”
- Not in the sourcesU.S. think tanks and Congress warn that Beijing may be preparing to disrupt communications in a crisis.Latest from Tom's Hardware: “A U.S. congressional report from 2025 highlighted that China is actively developing techniques to cut cables”
- SupportedThe CSIS report described China’s efforts as “disproportionate.”Latest from Tom's Hardware: “the report made clear that the efforts were “disproportionate.””
- SupportedClaffey is quoted as saying “subsea cables are digital lifelines” and that “the U.S. and its allies must protect them in peacetime to stay connected in crisis.”Latest from Tom's Hardware: “Claffey warns that “subsea cables are digital lifelines,” arguing that “the U.S. and its allies must protect them in peacetime to stay connected in crisis.””