Africa's only surviving population of northern white rhinoceros has been reduced by 50% in the last 14 months due to poaching, conservationists say.
The Garamba National Park is the last refuge for these majestic animals
IUCN, the World Conservation Union, says there are between 17 and 22 animals left in their last refuge in Democratic Republic of Congo (DRC).
This represents a loss of between 14 and 19 rhinos in 14 months since the last survey - a 50% crash in numbers.
Heavily-armed poaching gangs are being blamed for the slaughter.
"It is devastating and deeply frustrating to see fresh rhino and elephant carcasses throughout the southern sector," said Kes Hillman Smith of the Garamba National Park Project.
"We have been fighting to save these rhinos and elephants and the Garamba Park for 23 years. It is ironic that now as peace is supposed to be coming to the region, the exploitation of large mammals has escalated."
The northern white rhino was once widespread, with an estimated 2,250 individuals across five African states in 1960.
But in the ensuing years, poaching devastated populations. By 1984, numbers had fallen to 15 animals, all restricted to the DRC's Garamba National Park.
In 1996, the national park was placed on the List of World Heritage in Danger and conservationists made a plea for international support to save the endangered population.
Conservation efforts subsequently helped numbers stabilise, despite occasional set-backs caused by poaching and political instability.
A comprehensive survey carried out in April 2003 showed a minimum of 30 northern white rhinos living in the park.
However, an intensive aerial survey of the Garamba National Park, carried out from 7 to 11 July this year counted a minimum population of between 17 and 22 animals, despite the birth of four calves in 2004.
Increasing numbers of heavily-armed poachers, including ones from neighbouring Sudan, are known to be operating in the area and are said to be responsible for the recent slaughter.
Despite some successes, the rhinos do not generally breed well in captivity
The park's guards are struggling to contain this insurgency and several have lost their lives in anti-poaching operations, the IUCN reports.
Apart from a temporary recovery in the early 1970s, the northern white rhino has never managed to emulate the recovery of its southern relative.
The southern white rhino has increased from approximately 50 individuals in 1895 to over 11,000 today.
An emergency conservation strategy for the northern white rhino was drawn up in 2003 and put into immediate effect.
The IUCN says a long term strategy is needed, but that the current priority is to secure the survival of the remaining animals.
It also adds that more support is required to bolster the Garamba National Park's force of guards.
"A number of organizations have now pledged support, without which all rhinos could be lost within a year," said Fraser Smith, Garamba project leader, "But we still have a long way to go to make it work on the ground."
The western black rhinoceros is in a similarly precarious position. Although the continental population of black rhinos has slightly improved after a period of devastating poaching losses, this sub-population has been reduced to a about 10 isolated individuals in northern Cameroon.