China has completed the construction of two lighthouses in the disputed South China Sea, the official Xinhua News Agency reported late Friday. The news comes as China warned Friday against “provocative behavior” in its territorial waters.

A completion ceremony was held for the lighthouses on Cuateron Reef and Johnson South Reef in the Spratly islands. The construction has been reportedly opposed by the U.S. and the Philippines, who are concerned that China's land reclamation projects around reefs and atolls could be used to base military planes and navy ships. The latest move has raised further worries over Beijing’s maritime ambitions.

According to Xinhua, the two lighthouses will greatly improve the navigational conditions and reduce navigational risks and accidents in South China Sea as it will provide route guidance, safety information and emergency rescue, and other public services to vessels in the waters.

China's ministry of transport also said it will continue the construction of other installations to improve the navigation services.

China claims most of the energy-rich South China Sea, parts of which have also been claimed by the Philippines, Vietnam, Malaysia, Taiwan and Brunei.

China said Friday it would not stand violations of its territorial waters as the U.S. military plans to sail warships close to the 12 nautical-mile zones around artificial islands built by China in the Spratly chain. However, neither the U.S. Defense Department nor U.S. President Barack Obama’s administration has confirmed the reports.

China has been paying close attention to the reports of looming U.S. naval action, according to Hua Chunying, Chinese foreign ministry spokeswoman, and has maintained “extremely thorough communication,” about the South China Sea dispute with the U.S.