The world's largest surviving population of white rhinos suffered its heaviest toll on record last year when poachers killed more than 1,000 of the threatened animals to feed an international market for trinkets and potions made from their horns. The South African Department of Environmental Affairs reported Friday that it had counted 1,004 rhinos killed by poachers in 2013, mostly in Kruger National Park, along the porous border with Mozambique. It was the worst year for rhinoceros poaching since the government began tracking the illegal hunting in the early 1900s, National Geographic reported. South Africa is home to more than 20,000 white rhinos, about 80% of the world's population of the iconic beasts that numbered 500,000 a century ago, conservation organizations report. Soaring demand for rhino horn from Asian countries, particularly China and Vietnam, is driving up prices for the slain animals' signature feature, nurturing an illegal poaching network operating out of Mozambique, explained Tom Milliken, rhinoceros expert with the global wildlife trade monitoring organization TRAFFIC. "South Africa and Mozambique must decisively up their game if they hope to stop this blatant robbery of southern Africa's natural heritage," Milliken said, calling on authorities to make 2014 "the turning point where the world, collectively, says "enough is enough" and brings these criminal networks down." In its quest to protect rhinos from poachers, the South African government has signed agreements with China and Vietnam to better coordinate their tracking and enforcement efforts. Similar agreements are in the works with Mozambique, Thailand, Laos, Cambodia and Hong Kong, TRAFFIC said on its website. "The world's rhinos are facing a genuine crisis, and high-level agreements and statements have to translate into meaningful conservation action, both in rhino range states and in key consumer countries such as Vietnam and China," said Naomi Doak, a coordinator for the wildlife group in Vietnam. We are still waiting to see the rhetoric result in significant arrests and prosecutions of those orchestrating the rhino horn trafficking. Last year's white rhino toll was nearly 50% higher than in 2012, when 668 of the animals were slaughtered for their horns. Interception and detention of poachers was up commensurately, with 343 alleged poachers and traffickers arrested in 2013, an increase from 267 the previous year, according to the report from Pretoria. But the numbers of rhinos killed nonetheless remained on track to overtake births within the next two to three years, Save the Rhino reports in its statistical analysis of the threatened species. Popular Science magazine calculated that at the current rate of poaching, white rhinos would be extinct in about 20 years. It also disputed Asian rhino horn consumers' belief that the ground extremity has medicinal value, describing its composition as similar to human fingernails. The London Conference on Illegal Wildlife Trade, which next month brings together senior officials from 50 countries, will seek to strengthen commitments to fight trade in endangered species and curb demand in the most voracious markets, the organization said of the gathering to be convened by Britain's Prince Charles and Prime Minister David Cameron.