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

The deadly conflict on the Thai-Cambodian border pits a longtime United States ally with decades of experience against a relatively young armed force with close ties to China.

China faces a delicate balancing act as it decides what role it should play in the ongoing border hostilities between Thailand and Cambodia, two South-east Asian nations that are its close neighbours and which it wields strong influence over.

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.

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.

BEIJING: China called for calm and proper handling of the border conflict between Cambodia and Thailand and reaffirmed its willingness to continue to play a constructive role in promoting de-escalation.

Residents in Thailand's Surin province bordering Cambodia ran for cover as the neighbouring countries exchanged fire, with weeks of tension over a border dispute escalating into clashes that have killed at least two civilians.

Cambodia has shipped its first batch of fresh durians to China after receiving final permission from the latter’s customs authority earlier this month.