"The U.S. already flunked the test and that should be a wakeup call," a former senior U.S. State Department official told Newsweek.

China urged Cambodia and Thailand to resolve their border dispute through friendly dialogue, offering to play a constructive role by upholding an "objective and fair" position, its foreign ministry said.

Tens of thousands of people sought refuge as border fighting between Thailand and Cambodia entered its third day Saturday, heightening fears of an extended conflict with the total death toll reaching 32.