But after a two-day Asia-Pacific summit, they vowed to work towards an "ambitious outcome" in Copenhagen.

Leaders, including the US and Chinese presidents, also vowed to pursue a new strategy for growth after the world's worst economic crisis in decades.

They resolved to conclude the Doha round of global trade talks in 2010.

In a joint declaration issued at the end of their two-day annual summit, they said: "We firmly reject all forms of protectionism and reaffirm our commitment to keep markets open and refrain from raising new barriers to investment or to trade in goods and services."

They also agreed to keep stimulus spending in place until a recovery was seen.