Poachers seeking horn for traditional medicines are driving once-thriving populations of rhinos in Africa and Asia toward extinction, global nature protection groups said yesterday.

In a report issued in Geneva, they said illegal slaughter of the already endangered animals is rising fast, with rates hitting a 15-year high amid stepped-up activities by Asian-based criminal gangs feeding the demand for horn.

"Illegal rhino horn trade to destinations in Asia is driving the killing, with growing evidence of involvement of Vietnamese, Chinese and Thai nationals in the illegal procurement and transport of the horn out of Africa," the report declared.

"Rhinos are in a desperate situation," said Susan Lieberman of the Swiss-based environmental body WWF-International, which issued the report together with the International Union for the Conservation of Nature.

The report, presented to a meeting of the UN-sponsored CITES agency which works to prevent trade in endangered species, said South Africa and Zimbabwe were seeing a particular surge in poaching.

While between 2000 and 2005 a relatively low total of three rhinos were estimated to have been illegally killed each month in Africa out of a total population of some 18,000, 12 were now being slaughtered monthly in the two countries alone.

In India, 10 of the animals had been slaughtered for horn since January and at least seven in Nepal, out of a total population for the two countries of just 2,400, the report said.