U.S. Joint Chiefs of Staff Admiral Mike Mullen has openly criticized China's response to the sinking of the South Korean warship "Cheonan."

Speaking Wednesday (local time) at the Asia Society Washington Awards Dinner, Admiral Mullen said he was disappointed with China’s "tepid response to calls by the international community for support" on the Cheonan issue.

He also said the Pentagon remains concerned that China is unwilling to engage with U.S. military leaders. During a trip to Asia last week, Secretary of Defense Robert Gates was not invited to meet with top Chinese military officials.

Admiral Mullen accepted the Public Policy Award on behalf of the U.S. armed forces at the event.