Thai police officials have trekked into mountains with shovels to dig up shallow graves after the grim discovery of an abandoned jungle camp that has cast a new spotlight on the human trafficking networks operating in Thailand.

Police Gen. Jarumporn Suramanee says at least five corpses were found by Saturday afternoon as efforts continue to dig up about 30 gravesites scattered around a camp tucked in a forested area of southern Thailand.

The cause of the deaths is not immediately clear. But the discovery of the hidden mountain camp is a sharp reminder that trafficking continues in Thailand despite repeated assurances by authorities that they are addressing the root causes.

Human Rights Watch says discovery highlights that the trafficking situation in Thailand is "out of control."