Poachers have killed 57 rhinos in South Africa's national parks since the beginning of the month, a rate of almost two a day, officials said Thursday.
Despite stepped-up anti-poaching operations, the Department of Environmental Affairs said 42 rhinos alone had been poached in Kruger National Park, a vast wilderness that straddles the Mozambique border.
The park authorities blamed the staggering rate of kills on "recent floods in the Kruger National Park, thick vegetation, two weeks of a full moon, aggressive incursions from Mozambique".
Authorities said 18 suspected poachers have been arrested from January 1, and seven rhino horns recovered.
Four poachers were killed in gun battles with anti-poaching forces.
Some suspects were found in possession of heavy calibre hunting rifles and ammunition.
South African National Park (SANParks) chief executive David Mabunda believes that anti-poaching operations were starting to yield results, despite increased incursions from Mozambique.
"Our operations are more militaristic. The number of poachers arrested has increased inside and outside the park," Mabunda said.
The vast Kruger Park, which is the country's top safari destination, accounts for 40 percent of the world rhino population.
In 2012, a record 668 rhinos were slaughtered in South Africa, due to a booming demand for their horns, which some people in Asia believe have medicinal properties.
The claim is widely discredited.
The hard-hit Kruger mega reserve has set up a scam-watch page warning of bogus rhino schemes.
It lists examples of adverts claiming to have horns for sale -- with some of the advertisers posing as staff of the reserve.
"They mention that they are from SANParks and that is not true," SANParks spokesman Ike Phaahla told AFP.
One poster claiming to be a Kruger worker offered five kilogrammes of horn for sale at $3000 (2,200 euros) per kilogramme, showing a picture of a horn on a scale.
Interested parties are asked to get in touch "for more information for long business relationship".
The park said it was concerned by the bogus sales ads and by people trying to exploit the anti-poaching drive with illegal fund-raising schemes.
South Africa has had a moratorium on rhino horn sales since 2009.
South African authorities have stepped up anti-poaching operations in the Kruger Park, including deploying the army to the park along with a surveillance aircraft.