South African officials say poachers have killed 57 rhinos across the country this month, despite increased anti-poaching operations.
A record number of rhinos were slaughtered in South Africa last year, raising concern that park rangers and others fighting the poachers are being outgunned and overwhelmed.
Thursday's report says most of the January killings occurred in Kruger National Park, a vast wilderness area along the Mozambique border. South Africa's Department of Environmental Affairs says 42 rhinos have been killed in the park since the start of the year.
It says recent flooding may have helped poachers because the water left large sections of the park inaccessible to vehicles and park rangers. Officials also say there have been "aggressive incursions" from Mozambique.
A record 668 rhinos were slaughtered in South Africa in 2012. The killings are driven by a high demand for rhino horns, especially in Asia where the horns are believed to have medical benefits.
Researchers have found those beliefs to be unfounded.
South Africa is home to about 80 percent of the world's rhino population.
A South African parks official says anti-poaching operations are beginning to yield results in Kruger National Park, in spite of this month's rhino deaths.
In a Thursday statement, SANParks CEO David Mabunda said anti-poaching operations are becoming "more militaristic" and the number of poachers arrested inside and outside of the park had increased.
Officials say a total of 18 suspected poachers have been arrested this month.
Also, officials in South Africa and Vietnam signed an agreement in December to work in tandem to decrease the illegal trade of rhino horns. The plan calls for cooperation between law enforcement officials, a mutual compliance with international poaching laws and strong anti-poaching legislation in both countries.
Separately, some South African conservationists and wildlife reserve owners have begun calling for the legalization of the rhino horn trade, saying it would reduce the price and incentive for poaching.