Asia-Pacific leaders meeting in China have agreed to move towards a new free trade zone strongly backed by Beijing.
The Free Trade Area of the Asia-Pacific (FTAAP) is seen by some as a rival to a US trade pact, which excludes China.
The Apec summit near Beijing agreed to launch a study into the FTAAP.
Chinese leader Xi Jinping, who earlier urged Asia-Pacific nations to accelerate economic ties, described the endorsement of the pact as a “historic” decision.
The US is currently negotiating a separate Trans-Pacific Partnership (TPP), which is considered part of Washington’s “pivot” towards Asia – ensuring continued US influence in the region in response to growing Chinese power.
The TPP involves 12 countries, but not China or Russia.
Mr Obama has rejected suggestions by Chinese commentators that the TPP is a way of countering Chinese influence.
In an interview with China’s Xinhua state news agency, he said the US was in no way trying to contain China.