Chinese researchers have developed a compact, deep-sea device capable of severing even the most fortified underwater cables.

The development raises concerns that Beijing could target critical communication and power lines, especially in the event of a Chinese invasion of Taiwan.

The tool can slice armoured cables at depths of up to 4,000 metres (13,123 feet), which is twice the maximum operational range of existing subsea communication infrastructure, according to an academic paper seen by the South China Morning Post.

While the cutting tool was developed for civilian salvage and seabed mining, it will raise alarm bells amid fears China and Russia are becoming increasingly brazen in deploying “grey zone tactics” to assert their influence and isolate adversaries.

The new technology contains a six-inch diamond-coated grinding wheel, which can spin at 1,600rpm – giving Beijing the ability to slice through deep-sea cables layered with steel, rubber and polymer sheaths.