British police said Saturday they have stepped up security around wildlife parks after conservationists warned their critically-endangered black rhino were being targeted by poachers.
The Aspinall Foundation, a wildlife charity which runs two animal parks in Kent in southeastern England, has also appealed for volunteers to help keep watch for any suspicious activity.
Police constable Michael Laidlow, wildlife crime officer for the Kent force, said they had received an anonymous tip-off about a possible attack on rhinos.
"All our wildlife officers are aware of the information and we're taking steps to increase patrols in the area," he said.
The Aspinall Foundation's chairman, Damian Aspinall, said police had told them there was a "genuine threat" which it attributed to poachers seeking the rhinos' valuable horns.
"It is tragic and beyond belief that, as we do everything possible to restore these magnificent animals safely to the wild, the traders who seek to profit from their slaughter should bring their vile activities to the UK," he said.
The foundation has 20 black rhinos across its two parks in Kent, out of an estimated 200 held in captivity around the world and just 700 who survive in the wild.
It claims to have successfully bred 33 baby black rhino in captivity over the last seven years, and three animals were returned to the wild in Tanzania in East Africa nine months ago.
Rhinos are victims of a booming demand for their horns, which some people in Asia think have medicinal properties. The medical claim is widely discredited.