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".

Trump gets through to both sides by citing the advantages of coming to terms rather than risking important trade deals with Washington.

Thailand and Cambodia exchanged heavy artillery fire on Friday as their worst fighting in more than a decade stretched for a second day, despite calls from the region and beyond for an immediate ceasefire in an escalating border conflict that has killed at least 16 people.

At least 12 have been killed in violent tensions along the disputed border separating Thailand and Cambodia. This follows a flare-up in May in which troops exchanged fire.