Beijing has claimed it has discovered "underwater lighthouses" and other devices that are allegedly being used for surveillance purposes by China's adversaries.

China's Ministry of State Security took to WeChat to make the accusations, explaining Chinese authorities discovered several devices that were all designed to gather information on their surrounding area, which was in the ocean. More specifically, China explained that it found drifting devices capable of "detecting and grasping the real-time situation in the sea area," with others that acted as "underwater 'lighthouses' to show the direction of submarines of other countries that have intruded into China's waters."
Beijing said the discovered devices were designed with the purpose of "covertly collecting marine hydrological information and data on the activities of various ships around them and serving the preset of the battlefield environment." Additionally, China alleged it discovered a base embedded into the seafloor, which is reminiscent of an allegation the nation made back in May of this year where it said it discovered "maritime espionage" within its waters when a fishermen allegedly said he found the above device.
"These devices have a variety of functions, not only to realize the dynamic perception of sensitive data, detection and collection, but also to store data, analysis, transmission and other functions," wrote the ministry back in May. "Most devices also have a self-destruct function, which can be automatically destroyed after the completion of the mission according to a pre-set program."