Thailand and Cambodia exchanged fire along their disputed border for a second day on Friday, officials from both countries said, with more than a dozen people reported killed and more than 100,000 civilians evacuated.

Armed clashes broke out Thursday between Thailand and Cambodia in long-disputed border areas, rapidly escalating months-long tensions.

"Cambodian forces have conducted sustained bombardment utilising heavy weapons, field artillery, and BM-21 rocket systems," it said in a statement.