With much of the formal summit activity, including a working lunch, concentrated over a few hours, Mr. Obama underscored the importance of APEC's trade liberalization priorities for the global economy and the United States.

　　Addressing the opening session, the president said the nearly three billion people in 21 APEC countries are looking to the three-decade-old organization to create opportunities through expanded trade that will boost economic growth and create jobs.

　　APEC's goals of slashing tariffs and removing trade barriers, Mr. Obama said, are critical for the U.S. economic recovery. "The Asia-Pacific region is absolutely critical to America's economic growth.  We consider it a top priority.  And we consider it a top priority because we are not going to be able to put our folks back to work and grow our economy and expand opportunity, unless the Asia-Pacific region is also successful," he said.

　　Mr. Obama said the region is key to his objective of doubling U.S. exports, adding that APEC economies need to work together to spur "quicker, sturdy and sustainable" economic growth.

　　A final APEC statement is expected to point to progress toward creating what Mr. Obama referred to as a "seamless regional economy," with agreements aimed at boosting trade and investment by promoting "green" jobs, innovation, and streamlining and coordinating regulations.

　　The United States and eight other APEC nations already have announced agreement on "broad outlines" to create a new Trans-Pacific Partnership trade group, or TPP, that Mr. Obama says would be a model for broader open regional trade.

　　In addition to the United States, other TPP participants include Australia, Brunei, Chile, Malaysia, New Zealand, Peru, Singapore and Vietnam. China has been critical of the grouping, saying it reflects protectionist tendencies in APEC.

　　U.S. officials say Mr. Obama was expected to hold additional talks on the sidelines of the summit with Chinese President Hu Jintao.  In their main meeting on Saturday, the two men discussed trade and differences over China's currency policies.

　　The issue of Iran's nuclear program and a recent International Atomic Energy Agency report that provided evidence of secret Iranian weapons development efforts have also been a focus of Mr. Obama's meetings with the leaders of China and Russia.

　　U.S. officials say China and Russia remain supportive of continuing diplomatic steps aimed at preventing Iran from obtaining a nuclear weapons capability.

　　Mr. Obama says that he and Russian President Dmitry Medvedev agreed to work to "shape a common response" on Iran against the backdrop of the nuclear report.  U.S. officials say consultations will continue about the next steps to increase pressure on Tehran.