BEIJING, Nov. 17 (Xinhua) -- China and the United States would work together for positive results at the Copenhagen summit slated for December this year, Chinese President Hu Jintao said here on Tuesday.

    "President Obama and I agreed to expand the China-U.S. cooperation in the fields of climate change, energy and environment," Hu told the press after talks with visiting U.S. President Barack Obama.

    China and the United States would cooperate with all sides concerned, on the basis of the "common but differentiated responsibilities" principle and their respective capabilities, to help produce positive results at the Copenhagen summit on climate change, said Hu.

    China and the United States have signed documents of cooperation including a memorandum of understanding on enhancing cooperation on climate change, energy and the environment, and have officially launched an initiative on a joint research center on clean energy, he added.