China has revealed a deep-sea cable-cutting device capable of severing even the most heavily fortified underwater communication and power cables deep in water. The technology is developed by the China Ship Scientific Research Centre (CSSRC) and the State Key Laboratory of Deep-Sea Manned Vehicles. It has sparked concerns over the security of global undersea infrastructure. Notably, 95% of global data transmission and support for critical military and civilian operations is conducted through deep sea cables.
This is the first time any nation has publicly disclosed possessing such a capability. It signalled an advancement in deep-sea operations with both civilian and military implications. The cutting-edge tool is designed to integrate with China’s advanced submersibles, including the Fendouzhe (Striver) and the Haidou series, allowing for precision operations in extreme underwater environments.
Unique Capabilities
According to reports available, the newly developed device can operate at depths of up to 4,000 meters (13,123 feet), which is twice the maximum depth of most existing undersea communication infrastructure. Traditional methods of severing cables have struggled due to the heavily reinforced steel construction of these vital lines.
To overcome these challenges, a research team led by engineer Hu Haolong developed a 150mm (six-inch) diamond-coated grinding wheel that spins at 1,600 rpm. This powerful tool generates the required force to shatter steel while minimizing disturbances to surrounding marine sediment.
On February 24, a paper in the Chinese-language journal Mechanical Engineer, a peer-reviewed journal in the Chinese language, published the device is powered by a one-kilowatt motor with an 8:1 gear reducer, which ensures a balance of torque and efficiency. However, prolonged use at extreme depths may lead to overheating and limit its operation.
In order to face water pressure at 4,000 meters—exceeding 400 atmospheres, the tool is confined in a titanium alloy shell with oil-compensated seals. The device is also equipped with robotic arms to allow it to operate at near-zero visibility.
Implications
Officially, China has stated that the device is for civilian purposes. It includes seabed mining and salvage operations. However, the dual-use nature of the device has caused unease among nations. The incidents of destroying undersea cables have become extremely common nowadays. With this technology, China can secretly sabotage strategic subsea cables for geopolitical gains.
Most at risk is likely to be cables near Guam that could be physically disrupted. A key location within the US Indo-Pacific strategy is Guam, home to more than a dozen fiber-optic lines that support civilian and military networks, including the Google-operated cables. Damage to these communications lines in an attack could wreck global communications as well as wartime readiness in times of crisis.
Russia has also been compared to its alleged role in undersea cable-cutting activities. Since 2023, 11 underwater cable damages have been reported in the Baltic Sea. These have energized speculations of coordinated grey-zone warfare actions between China and Russia.
Taiwan, in particular, has reported an alarming spike in suspected Chinese cable sabotage. In February 2025, Taiwanese authorities seized a Togo-flagged cargo ship, Hong Tai 58, crewed by Chinese workers, after it was linked to the severing of an undersea telecom cable. According to media reports, Taiwan has recorded five such incidents this year alone, compared to three cases in both 2023 and 2024, suggesting an increasing trend in attacks on subsea infrastructure. The several incidents of damaged Undersea cable in the backyard of Russia (Baltic Sea) and China (South China Sea) have raised concerns about the possible involvement of these two powers in it.
Also Read: CCP prowling: Undersea Cables damaged near Taiwan, Chinese Ship detained
Chinese maritime expansion
China currently has the largest fleet in the world and has emerged as a top ocean power. In February 2025, construction on a 2,000-meter-deep underwater “space station” in the South China Sea started, with room to house at least six people for month-long expeditions. The facility is likely to further China’s strategic presence in disputed waters considerably.
At the same time, the US is having difficulty keeping up. The US has an ageing deep-sea fleet constraining its capacity to respond to China’s growing maritime capabilities. Another major regional power, Japan, is also having trouble as its sole manned submersible, the Shinkai 6500, is approaching retirement with no successor on the drawing board.
Despite rising concerns, the Chinese research team has repeated that the cable-cutting device is primarily intended for marine resource development rather than military applications. In their published paper, they wrote, “Nations are now compelled to redirect their resource exploitation focus towards the seas. The 21st century is the century of the oceans. Enhancing marine resource development capabilities, advancing the blue economy, and building China into a maritime powerhouse constitute critical components of realizing the Chinese dream.”
Allegations of Sabotage
Amid increased suspicions over recent submarine cable cuts in the Baltic Sea and the Taiwan Strait, China has repeatedly affirmed that the country is committed to protecting undersea cables. In order to show the world how much China cares about the undersea infrastructure, the China Information and Communication Research Institute, a state-affiliated entity released a report where they mentioned Beijing’s role in the construction and protection of global submarine cable networks.
Despite all these affirmations, scepticism remains in countries’ minds about China’s role in undersea cable damage. Putting energy and resources into building undersea cable cutter technology creates suspicion because no other countries have put resources into developing technology which have the capacity to cut undersea cables. China understands the geopolitical relevance of the undersea cable in terms of data transfer and military communication and has came up with a technology to destroy it in the time of war and tension. Given China’s history of grey-zone tactics and the increasing reports of undersea cable damage, international security experts closely monitor Beijing’s growing capabilities in deep-sea operations.
Geopolitically, the undersea cable has become an important area of collaboration and contestation in international politics. Hence, the new undersea cable cutter has the capacity to evolve the nature of modern maritime conflicts, where infrastructure destruction could play a decisive role in shaping global power dynamics.
As geopolitical tensions rise, the development of China’s deep-sea cable-cutting technology underscores the evolving nature of modern maritime conflicts, where infrastructure disruption could play a decisive role in shaping global power dynamics.
