United States President Barack Obama and Prime Minister Wen Jiabao of China have discussed territorial disputes that have raised tensions in Asia.
At a meeting on the sidelines of the South East Asian summit in Bali, Mr Obama said Washington wanted to ensure sea lanes were kept open and peaceful - a reference to China's disputes with some of its neighbours in the South China Sea.
China lays claim all of the sea, while other South East Asian nations claim parts of it. China has warned outside forces to stay out of the dispute.
The BBC reports the South China Sea holds potentially vast reserves of oil and gas and is an important shipping route.
On Friday, Mr Wen warned "external forces" not to get involved.
On Thursday in Australia, Mr Obama pledged an increased US engagement with the region and a strong military presence, including the deployment of US Marines in northern Australia.