WASHINGTON - The United States and China will cooperate and build "closer economic ties" through dialogues, the US Treasury Secretary Timothy Geithner said on Monday.

"Over the next two days, we will have a chance to discuss the opportunities for closer economic ties," Geithner said at the economic track opening session of the third round of U.S.-China Strategic and Economic Dialogue (S&ED) which kicked off here in Washington DC.

The two sides will also "address areas of concern" and to " share perspectives on the major challenges facing each of us at home as well as in the broader global economy," Geithner said.

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"I believe we are making significant progress in strengthening our economic relationship," he added.

The two-day S&ED is co-chaired by Chinese Vice Premier Wang Qishan, State Councilor Dai Bingguo and US Secretary of State Hillary Clinton and Treasury Secretary Timothy Geithner.

The dialogue mechanism was upgraded from former Strategic Dialogue and biennial Strategic Economic Dialogue, which were initiated by the two heads of state in 2005 and 2006, respectively.

Geithner said that the key challenge that the US economy is facing remains the high unemployment, currently at 9.0 percent.

"Even after a year and a half of positive economic growth and more than two million private sector jobs created - unemployment is still very high, and we still have a lot of work to do in repairing the damage caused by the crisis," he said earlier at the joint opening session of the S&ED.

"Our challenge is to strengthen the foundations for future economic growth. This requires a sustained effort to improve education and improve incentives for innovation and investment, even as we put in place the long term fiscal reforms that force us once again to live within our means as a nation."

The Secretary said that cooperation between US and China contributed "no small part" to the global recovery. And the continuing effort of working together will benefit the sustaining growth of the world.

He quoted the Chinese saying "Share fortunes together, meet challenges together" to call for further economic cooperation between of the two major players of global economy.

China is the United States' second-largest trading partner and its third-largest export market, with bilateral trade totaling about $385 billion in 2010, according to Chinese customs statistics.