Talks between US secretary of state Hillary Clinton and Chinese leaders have failed to narrow gaps on how to end the crisis in Syria and resolve Beijing's territorial disputes with its smaller neighbours over the South China Sea.
Mrs Clinton, who met president Hu Jintao and foreign minister Yang Jiechi, wants China to stop backing the regime of Syrian president Bashar Assad, and has been pushing for the country to be more flexible in lowering tensions over the oil-rich South China Seas.
But comments from Mrs Clinton and Mr Yang showed that the two countries remain divided on those issues, although both said they were committed to working together.
The US and other countries are upset that China and Russia have repeatedly used their veto powers at the UN Security Council to block actions that could have led to sanctions against Mr Assad's regime.
China says Syria's civil war needs to be resolved through negotiations and not outside pressure.
"I think history will judge that China's position on the Syria question is a promotion of the appropriate handling of the situation, for what we have in mind is the interests of the people of Syria and the region," Mr Yang said at a news conference given with Mrs Clinton.
Mrs Clinton responded by saying the violence was boiling over into other countries and that strong backing should be given to the Security Council. "It is no secret that we have been disappointed by Russia and China's actions blocking tougher UN Security Council resolutions and we hope to continue to unite behind a real path forward to end the violence in Syria," she said.
Mrs Clinton had also been scheduled to meet vice president Xi Jinping, who takes over as China's top leader later this year, but that was cancelled. "The Chinese side has cited unexpected scheduling reasons for the cancellation of the Secretary's meeting with Vice President Xi," said a senior US state department official.
A meeting between Mr Xi and the visiting prime minister of Singapore, Lee Hsien Loong, was also cancelled without explanation. Mr Yang would say only there should not be "unnecessary speculation".
Before meeting Mr Hu, Mrs Clinton said the US-China relationship is strong. "We are able to explore areas of agreement and disagreement in a very open manner, which I think demonstrates the maturity of the relationship and the chance to take it further in the future," she said.