Poachers have slaughtered at least 200 elephants in the past five weeks in a patch of Africa where they are more endangered than anywhere else on Earth, wildlife activists say.
The International Fund for Animal Welfare warned that the money made from selling elephant tusks was fuelling misery throughout the continent.
Many elephant calves orphaned by the recent killings have been spotted in Cameroon's Bouba Ndjida National Park and activists fear the animals may soon die of hunger and thirst.
"Their deaths will only compound the impact of the poaching spree on Cameroon's threatened elephant populations," the organisation said.
The fund blamed poachers from Sudan, who it said were crossing through Chad to reach the remote northern Cameroon wildlife reserve. Ongoing shooting was making it impossible to conduct a detailed assessment, activists said.
The fund said the problem had existed for years but the scale of this year's killings was "massive and unprecedented".