Thailand and Cambodia clashed for a fourth day on Sunday, despite US President Donald Trump warning them they are risking potential trade deals with the US. The US president said on Saturday the leaders of the two countries had agreed to meet to negotiate a ceasefire.

The Thai warning came as the U.S. expressed its grave concern about the most serious fighting in years between the Southeast Asian neighbors. The U.S. and China compete for influence in fast-growing Southeast Asia, and both have good relations with Thailand and Cambodia.

The latest flare-up started on Thursday, with intense fighting spreading across multiple border areas. Early Saturday, Thailand’s navy joined the army in repelling what it described as incursions by Cambodian troops at three points in eastern Trat province.

Thai and Cambodian troops clashed in at least six areas along the countries’ shared 510-mile border on Thursday, killing one Thai soldier and nearly a dozen Thai civilians. The fighting—the second instance of armed confrontation between the two countries in almost two months—has sparked fears that the conflict could escalate into open warfare.

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

Thai men's top seed Kunlavut Vitidsarn swept aside Malaysian Leong Jun Hao with a 23-21 21-7 win to march into the quarter-finals of the China Open on Thursday, while women's top seed An Se-young beat Sim Yu-jin 21-13 21-15 in an all-South Korean clash.

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.

Taobao, China’s leading online shopping platform under Alibaba Group Holding, is experiencing high user growth in Thailand after launching a localized version for the market.