Thai and Cambodian leaders are set to hold talks on Monday in a bid to end the deadliest clash between the two Southeast Asian nations in over a decade, a peace initiative driven by US President Donald Trump,

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

At least eight civilians were killed in attacks in a disputed border area between Cambodia and Thailand on Thursday, according to authorities. Thailand said Cambodian soldiers opened fire on a military base in Surin.