Deadly violence has flared up once again on the contentious border between Thailand and Cambodia, reigniting a long-running but little-known dispute.

People on both sides of the border share a cultural heritage much older than modern nation-states, dating back to the ancient Khmer civilization.

Thailand said on Friday it has evacuated more than 100,000 people along the Cambodian border as the two countries fight their bloodiest military clashes in over a decade.