Officials in Cameroon say 458 elephants have been slaughtered in recent weeks in an unprecedented wave of ivory poaching.
The International Fund for Animal Welfare said they were killed in the Bouba Ndjida National Park in northern Cameroon, near the border with Chad, by gangs from Sudan.
Many orphaned calves were spotted abandoned afterwards.
IFAW official Celine Sissler-Bienvenu said the scale of the killings this year is much higher than preceding years.
She said the ivory is smuggled to markets in Asia and Europe and the money is used to buy arms.