More than 1,300 rhinos were poached in Africa last year, a record since 2008 when South Africa banned trade in rhino horns, leading conservation body IUCN said on Wednesday.
"The number of African rhinos killed by poachers has increased for the sixth year in a row with at least 1,338 rhinos killed by poachers across Africa in 2015," the International Union for Conservation of Nature (IUCN) said in a statement.
"This is the highest level since the current crisis began to emerge in 2008," the Switzerland-based body said.
The slaughter has been driven by demand for their horn in countries such as China and Vietnam, where they are prized for their purported medicinal properties.
The horn is composed mainly of keratin, the same component as in human nails, but it is sold in powdered form as a supposed cure for cancer and other diseases.
Trade in rhino horns was banned in 1977 by the Convention on International Trade in Endangered Species (CITES), an international treaty created in 1973 to protect wildlife against over-exploitation, and ensure that trade in specimens of wild animals and plants does not threaten their survival.
But it was only banned in 2008 in South Africa,which is said to be home to 20,000 rhinos or 80 percent of the world's rhino population.
IUCN Director General Inger Andersen said despite stepped up surveillance by field rangers risking their lives daily there had been "alarming increases in poaching over the past year in other vitally important range states, such as Namibia and Zimbabwe" both of which adjoin South Africa.
Demand for rhino horn from South East Asia is being illegally supplied by sophisticated transnational organised crime networks, the IUCN said.
They are sold for about $60,000 a kilo on the black market, making it more expensive than cocaine.
"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 IUCN expert Mike Knight.
On the plus side, poaching in Kenya decreased over the past two years and went down for the first time in South Africa in 2015.
According to experts, there were between 19,000 and 21,000 white rhinos in Africa last year and between 5,000 and 5,500 black ones.