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".

A Cambodian government official has sung praise to U.S. President Donald Trump for "bringing about peace" after Thailand and Cambodia agreed to a cease-fire starting at midnight local time on Monday.

Thailand and Cambodia exchanged heavy artillery fire for a second day on Friday as border fighting intensified and spread, while Cambodia's leader said Thailand had agreed to a Malaysian ceasefire proposal but then backed down.