The US and China signed a document on climate change and clean energy that sets out a path for improving cooperation between the world's two leading polluters.
But there were few details on what the "memorandum of understanding" entails. Government officials from both countries suggested the two nations were no closer to resolving their differences over how much to reduce their climate-damaging emissions.
China and the US emit nearly half of the world's greenhouse gases blamed for global warming and are considered critical to the prospects of a new global treaty being reached at a major summit in Copenhagen in December.
China argues industrial nations bear a greater responsibility for addressing climate change, but the United States wants emerging powers like China to agree to their own international targets for limiting the growth of their emissions.
The signing ceremony is led by Secretary of State Hillary Rodham Clinton and Treasury Secretary Timothy Geithner from the US, and Chinese State Councilor Dai Bingguo and Vice Premier Wang Qishan.
