BEIJING - U.S. Secretary of State Hillary Rodham Clinton is urging China to work with the United States to coordinate a response to the sinking of a South Korean warship blamed on North Korea.

Opening two days of high-level U.S.-China talks in Beijing, Clinton said today that North Korea must be held to account for the incident that international investigators have determined was caused by a torpedo fired from a North Korean submarine. China is North Korea's main ally and has thus far remained neutral on the investigation.

South Korea planned to ask the U.N. Security Council later today to take up the matter, which it sees as a violation of the truce that ended the Korean War. U.S. officials say they have more work to do to convince China that North Korea was responsible for the ship sinking.

Clinton and Treasury Secretary Timothy Geithner also will be trying to convince China to free up its currency's fixed rate against the dollar amid a gathering crisis in Europe that threatens to stall a global economic recovery.