Full coverage: The South China Sea Issue

China has completed the construction of four lighthouses on reefs in the South China Sea to aid maritime navigation in the area.

The Ministry of Transport says the lighthouses on Huayang Reef, Chigua Reef, Zhubi Reef, and Yongshu Reef are already in operation. The ministry also said the lighthouses have significantly improved the security for vessels passing through waters in the area. Construction on the fifth one on Meiji reef is underway.

The five lighthouses stand between 50 and 55 meters. They are also multi-functional, equipped with huge modern rotating lamp devices and lanterns with a diameter of four-and-a-half meters. The lanterns can beam light to as far as 22 nautical miles. The lighthouses can also automatically identify vessels within its service range and double as communication towers.

"Construction and use of the five lighthouses show China's efforts to perform its international responsibilities. The lighthouses support navigation, search and rescue, navigation safety, fishery production, disaster prevention and relief, and other maritime services. They are equipped with automatic identification system and very high frequency stations, which can make them work like radio beacons to assist navigation and information exchange such as warnings and requests for help," said Xu Ruqing, chief of Maritime Affairs Department, China's Ministry of Transport.

South China Sea contains busy water lanes for oil transporations. There is high risk of collosions and strandings, which pose threats to ecological systems.