China announced in August that it plans to build lighthouses on five islands in the South China Sea, a move that goes against calls from the United States and the Philippines for a freeze on such activity to ease territorial tensions.
At least two of the islands may be in waters claimed by Vietnam.
The state-run China News Service said Chinese authorities had been surveying sites for lighthouses on five islands, known in English as North Reef, Antelope Reef, Drummond Island, South Sand and Pyramid Rock, according to news reports.
Drummond Island and Pyramid Rock are in the China-controlled Paracel Islands, which are more than 100 small coral islands and reefs also claimed by Vietnam and Taiwan.
In 2010, China completed construction of 13 stone tablets and lighthouses on islets in the East China Sea to mark its territorial waters in the oil-rich area, according to state media.