(CNN) Poachers slaughtered a record number of rhinos last year in Africa as demand for their horns skyrockets in Asia.
At least 1,338 rhinos were killed last year, the largest number since the poaching crisis intensified nearly a decade ago, according to data compiled by an international group.
The number of rhinos killed has gone up in the continent for six years in a row.
Despite the grim statistics, there was a ray of hope in South Africa, where the killings decreased slightly for the first time in years.
South Africa showed some improvement after aggressive anti-poaching efforts, but the overall number of rhinos killed increased in other nations.
Of the total number of rhinos killed in the continent last year, about 1,175 were in South Africa. The number is 40 less than rhinos killed in that country the year before.
"This is testimony to the valiant and enormous efforts underway -- often against overwhelming odds -- to curb the losses," said Inger Andersen, director general of International Union for the Conservation of Nature, which compiled the data.
"Sadly, these improvements have been dampened by alarming increases in poaching over the past year in other vitally important range states, such as Namibia and Zimbabwe."
South Africa is home to about 80% of Africa's rhinos, making it a crucial conservation hub for the iconic animal.
The killing of the animal has increased in recent years, fueled by a growing belief in Asia that its horns purportedly cure cancer.
As clients in countries such as China and Vietnam pay top dollar for rhino horns, poachers are getting brutal and sophisticated.
The demand has attracted global crime networks, complicating conservation efforts.
"The extensive poaching for the illegal trade in horn continues to undermine the rhino conservation successes made in Africa over the last two decades," said Mike Knight, chairman of African rhino specialists for the International Union for the Conservation of Nature.
Pressure is growing to protect the second-largest land mammal after the elephant.
The western black rhino was declared extinct five years ago as a result of poaching.
The northern white rhino, a subspecies of the white rhino, is near extinction. There are only three northern white rhinos left in the world, all living at a conservancy in Kenya.
The northern subspecies is believed to be extinct in the wild, according to the World Wildlife Fund, while the "near threatened" southern white rhino population is growing in sanctuaries.
All five remaining rhino species worldwide are considered threatened, according to the conservation group Save the Rhino.
Experts say if poaching continues at that rate, rhino deaths could surpass births, pushing the animals closer to extinction.
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