China has begun operating a lighthouse on one of its artificially-constructed islands in the South China Sea near which a US warship sailed last year to challenge China's territorial claims.
China claims most of the energy-rich waters of the South China Sea, through which about $5 trillion in ship-borne trade passes every year. But neighbours Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims.
China’s Transport Ministry held a completion ceremony on Tuesday for the 55-metre-high facility on Subi Reef in the Spratly Islands which contains technology to monitor passing ships.
The US guided missile destroyer USS Lassen sailed within 12 nautical miles of Subi Reef in late October, drawing an angry rebuke from China, which called the move "extremely irresponsible."
Subi Reef is an artificial island built up by China over the past year or so.
Xinhua reported last year that China would build two 50-metre-tall lighthouses on the Cuarteron and Johnson South reefs in the Spratly Islands, which are also claimed by Vietnam and the Philippines.
The state-run China Daily newspaper reported in 2014 that Beijing would build five new lighthouses on the South China Sea's Paracels chain.
Xinhua said the lighthouse, which emits a white light at night, "can provide efficient navigation services such as positioning reference, route guidance and navigation safety information to ships, which can improve navigation management and emergency response."
The South China Sea is an important maritime area and major fishing ground, it added.
"However, high traffic density, complex navigation condition, severe shortage in aids and response forces have combined to threaten navigation safety and hindered economic and social development in the region."