Speaking at the beginning of a meeting with China's President Hu Jintao, Obama said the two countries had "special obligations" to ensure nuclear stability and strong, stable economic growth.

Hu said China stood ready to work with the U.S. to create dialogue and increase cooperation.

U.S. concerns over China's currency hangs over the G-20 economic meetings in South Korea this week. The U.S. contends that China deliberately undervalues its currency, which gives it an unfair competitive edge.

China has taken issue with U.S. policies, as well. China downgraded U.S. debt, claiming the United States was depreciating the dollar.