"Although we believe chances are good that China and India will continue to rise, their ascent is not guaranteed and will require overcoming high economic and social hurdles," the report by the US National Intelligence Council said.
Titled "Global Trends 2025 -- A World Transformed," the 121-page report was released Thursday to stimulate debate and thinking as a new US administration prepares to take power.
It warned that US security and economic interests could face new challenges if China becomes a peer competitor with a strong military and a dynamic, energy-hungry economy.
"Few countries are poised to have more impact on the world over the next 15-20 years than China," the report said.
"If current trends persist, by 2025 China will have the world's second largest economy and will be a leading military power," it added.
"It could also be the largest importer of natural resources and an even greater polluter than it is now."
But it said China's economic growth wi