Chinese President Hu Jintao warned on Saturday that the global economy recovery was under threat and called for efforts to boost growth and liberalize trade.

"The global economic recovery is fraught with greater instability and uncertainty," Hu said during a speech in Honolulu ahead of a summit of Asia-Pacific leaders.

Referring to Europe's sovereign debt crisis, he said the world must remain committed to "ensuring strong growth in order to add momentum to the economic development of the Asia-Pacific and beyond."

President Barack Obama is hosting leaders from the 21-member Asia-Pacific Economic Cooperation (APEC) forum to its annual summit, held this year in his native Hawaii amid growing concern over Europe's woes.

Obama hopes to use the summit to get the ball rolling on a free trade agreement -- the Trans-Pacific Partnership, or TPP -- that his administration envisions as cementing America's role in the Asia-Pacific region.

Obama said nine nations had reached a "broad outline" on the TPP.

China, whose economic policies are often criticized by trading partners as protectionist, is not one of the nations involved but Hu voiced support for the idea in his speech.

"China supports steady efforts to promote the establishment of an Asia-Pacific free trade area and the realization of the goal of regional economic integration on the basis of" various proposals including the TPP, he said.

He made no mention of any Chinese plans to get directly involved in the pact, which could usher in one of the largest free trade zones in the world.

However, responding to earlier complaints by China that it had not been invited to the pact, US Deputy National Security Advisor Michael Froman told reporters members must first meet certain standards of trade liberalization.

"TPP is not something that one gets invited to. It's something that one aspires to," he said.

Hu said his government would do its part for the global recovery by continuing policies aimed at ensuring steady growth of China's increasingly powerful economy, now the world's second-largest after the United States.

"China's development constitutes an important force driving economic growth in the Asia-Pacific region and the world," he said, vowing also that China would get more deeply involved in Asia-Pacific economic cooperation efforts.

Hu added that China would work to increase imports -- a key demand of trading partners upset over habitual Chinese trade surpluses -- but made no mention of its controversial currency policy.

US Secretary of State Hillary Clinton on Thursday reiterated US calls for China to allow its currency to rise. Critics say the Chinese yuan is kept artificially low to boost exports.