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

Thailand favours bilateral negotiation rather than third-party mediation to resolve its military conflict with Cambodia, two Thai officials said, as fighting along their disputed border continued unabated.

China has blamed “Western colonialists” for ongoing clashes on the Thai-Cambodian border that have left at least 15 people dead and forced tens of thousands to flee their homes.

Both sides have accused each other of firing the first shot as border tensions between the two South East Asian neighbours heat up.

Thailand and Cambodia exchanged heavy artillery fire for a second day on Friday as border fighting intensified and spread, while Cambodia's leader said Thailand had agreed to a Malaysian ceasefire proposal but then backed down.

Thailand bombed Cambodia with F-16 fighter jets on Thursday, as relations between the two countries imploded following clashes on a disputed border near the Emerald Triangle.

Tensions have bubbled between the two neighbors for months, flaring on Thursday as Cambodia and Thailand exchanged fire.

Four dead as Tropical Storm Wipha tears through Thailand, China and into Vietnam - Heavy rain in China's eastern province of Shandong kills two people and leaves 10 missing