Full coverage: South China Sea Is Indisputable Part of China
The US president also raised the issue of the South China Sea dispute while in Vietnam. He said, "Big nations should not bully smaller ones, disputes should be resolved peacefully", which many saw as being aimed at Beijing.
China's Foreign Ministry reacted by saying: the county's size is not the yardstick in deciding what is right or wrong - and what remains vital is the legitimate desire to sincerely resolve disputes.
"We call for countries outside the region to respect our efforts in maintaining peace and stability, as well as the rules and order established by countries in the region in accordance with international law. We urge relevant countries not to threaten the sovereignty and security of the countries in the coastal areas in the South China Sea, and not to disturb the peace and stability in the region," said Chinese Foreign Ministry Spokesperson Hua Chunying.
China has been active in the region, reclaiming land, transforming small islands and reefs into artificial islands with buildings and airfields. Some of China's neighbors consider this a threat.
While the United States is insisting on free navigation of the South China Sea - and has sent some U.S. Navy ships and aircraft close to what China claimed its sovereign territory. U.S. critics of these moves say they're provocative - and more of a problem than a solution.
"The freedom of navigation patrols constitute a solution in desperate search of a problem. There really has not been interference with navigation and to be in China's face in this way with these patrols I think is needlessly provocative," said Ted Carpenter, senior fellow, CATO Institute.
As for its ongoing territorial disputes in the South China Sea - the Chinese Foreign Ministry says that border issues with 12 out of 14 neighbors have been resolved through negotiations, and rules of international law.
President Obama says the United States will continue to send its aircraft and ships wherever international law allows, and will support the right of all countries to do the same.
