The tank screeches as it rolls into the ad-hoc military base before four battle-weary soldiers jump out to re-inspect the hefty vehicle.

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.

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.

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