A forest protection ranger, a military police officer and a conservation worker have been killed in an ambush in northeastern Cambodia where illegal logging and smuggling are rife.

Keo Sopheak, a senior environmental official in Mondulkiri province, said the three-person team was attacked late Tuesday afternoon after patrolling in the Keo Siema wildlife conservation sanctuary. The dead civilian was a Cambodian employee of the New York-based Wildlife Conservation Society.

Keo Sopheak said the conservation team had confiscated chainsaws and motorcycles from some Vietnamese logging illegally.

But the official said the team was returning from their patrol when they were attacked and killed by Cambodian security forces, who are known to collaborate with illegal loggers who smuggle the wood to neighboring Vietnam.

Further circumstances of their deaths were not immediately clear.