Thai and Cambodian soldiers have clashed along the two countries' border in a major escalation of a festering dispute over territory that killed least 14 people, mostly civilians.

Tensions between the neighbors have escalated after a Cambodian soldier was killed in a skirmish earlier this year.

Border clashes between Thailand and Cambodia are nothing new. Disputes have persisted for more than a century along their 817km frontier, much of it poorly demarcated. A key flashpoint is the Preah Vihear temple, a 1,000-year-old Unesco World Heritage Site.