China's top admiral said his forces have shown "enormous restraint" in the face of U.S. provocations in the South China Sea, while warning they stand ready to respond to repeated breaches of Chinese sovereignty.

Beijing, which claims almost the entire energy-rich South China Sea through which $5 trillion in ship-borne trade passes yearly, has stepped up a program of land reclamation and construction in disputed islands and reefs there that has sparked concern in the Asia-Pacific region.

The United States has called for a halt to China's artificial island building, and in recent weeks has tried to signal its determination to challenge Beijing over the disputed sea by sending military ships and planes near the islands.