But he warned they stand ready to respond to repeated breaches of Chinese sovereignty.
Beijing, which claims almost the entire energy-rich South China Sea through which $US5 trillion ($7 billion) 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.