Cambodia and Thailand have a history of occasional conflict.
The two countries share a long and forested border with areas that both sides claim. There have been serious exchanges of fire in the past, too – in 2008 and 2011, clashes on a similar scale saw 40 people killed.
However, these were de-escalated relatively quickly.
Even as recently as this May, after an incident in which a Cambodian soldier was killed, both sides looked keen to prevent more violence, with meetings between army commanders from each country aimed at easing the tension.
But on 24 July, it erupted. Thai authorities say 12 people, all civilians apart from one, were killed.
