The U.S. says the Group of 20 meeting of finance ministers and central bank chiefs opening in the South Korean city of Gyeongju on Thursday should focus on exchange rates and nations’ current account imbalances.

A U.S. Treasury official said that the "conversations starting in Gyeongju and then continuing to Seoul will very much be centrally around this set of challenges we are facing --- the need for orderly adjustments to external imbalances, the need to move to more flexible exchange rates and to reduce the risks of excessive capital volatility."

He said the G20 needs to grapple with these economic challenges and do it in a way that results in a stronger framework for cooperative action.

The official said that some emerging countries are working to resist adjustments in line with market forces and are maintaining their currency values lower than the market rate for price competitiveness purposes.

The remarks reflect Washington's intent to use the G20 Gyeongju meeting to press China to appreciate the yuan.