China hosted a groundbreaking ceremony for the building of two lighthouses in the disputed South China Sea, state media said Tuesday, a move that is likely to escalate tensions in a region already jittery about Beijing's maritime ambitions.

China's Ministry of Transport hosted the ceremony for the construction of two multifunctional lighthouses on Huayang Reef and Chigua Reef on the disputed Spratly islands, state news agency Xinhua said, defying calls from the United States and the Philippines for a freeze on such activity.

The reefs are known in English as Cuateron Reef and Johnson South Reef.