U.S.-backed talks to end the border war, in which militaries have killed dozens of people and displaced hundreds of thousands, began on Monday in Malaysia.

A ceasefire between Thailand and Cambodia held and military commanders from both sides met to discuss measures to maintain the truce, as some residents along the disputed frontier trickled back home after five days of intense fighting.

Long-festering tensions over border territory have escalated into armed conflict between Cambodia and Thailand, leading to dozens of deaths on both sides and displacing tens of thousands of people.

After Bangkok rejected what it called the "baseless accusation" it had used chemical weapons over Cambodia during the Southeast Asian neighbours' bloodiest military clashes in decades, a months-old photo resurfaced in posts falsely claiming it showed the Thai air force using a "poisonous smoke weapon".

The State Department raised both advisories to Level 2 on July 25, citing the “risk of unrest” in Thailand and crime and landmines in Cambodia.