Conservationists say the elephant population in Mozambique has dropped nearly 50% in the last five years because of poaching, but cite good news from Uganda, where the elephant population is increasing.
Poachers have slaughtered tens of thousands of African elephants in recent years to meet demand for ivory, particularly in China.
Conservationists and governments have collaborated on an aerial, continent-wide census of elephants to better marshal efforts to protect wildlife.
The New York City-based Wildlife Conservation Society was involved in the Mozambique and Uganda counts.
The group said this week that the number of elephants in Mozambique had dropped from just over 20,000 five years ago to about 10,300.
But it says elephant numbers in Uganda have increased to more than 5,000 from fewer than 1,000 decades ago.