China's ambassador says the US shouldn't obstruct efforts by China and its neighbours to agree on a code of conduct in the disputed South China Sea.
Ambassador Cui Tiankai says the US has no territorial claim in those waters and should let countries in the region manage their disputes in a "friendly and effective way."
Beijing's island-building in the South China Sea has drawn criticism from Washington.
President Donald Trump departs later this week on a five-nation trip to Asia that includes a state visit to China.
The ambassador said North Korea will be a priority in talks between the Chinese and US presidents.
Cui warned that tensions over the North's nuclear programme could get more dangerous without more efforts to reach a negotiated solution.
