The US Fish and Wildlife Service (FWS) announced this week that it will take immediate action to protect the southern white rhino under the Endangered Species Act (ESA), thereby closing what it calls a "loophole" exploited by poachers and traffickers looking to cash in on the worldwide demand for rhino horn.

The loophole refers to the practice of traffickers mislabeling the horns of other protected rhino species as coming from the white rhino so as to avoid restrictions on sale and transport.

Secretary of Interior Sally Jewell said the action will protect the southern white rhino as a threatened species under the ESA "similarity of appearance" provisions and will strengthen international law enforcement efforts designed to crack down on what is being called a "poaching crisis."

"As both a transit point and consumer destination for illegal rhino horn products, the United States plays a vital role in curbing poaching and wildlife trafficking," Service Director Dan Ashe said in a statement.

According to Ashe, the FWS is exploring other "regulatory and policy options in an effort to strengthen our ability to investigate and prosecute poachers and traffickers."

Rhino poaching has reached unprecedented levels in recent years: in South Africa alone officials recorded 668 poachings in 2012 and 446 in the first six months of 2013.

Fueling the killing spree is an increasing demand for rhino horn, which, despite repeated medical testing proving otherwise, many cultures believe is capable of curing disease.

Of the five rhino species currently found in the wild, four are fully protected as endangered under the ESA. The white rhino is the fifth and includes two subspecies -- southern and northern white rhinos.

By 1970, southern white rhinos were only found in South Africa, though they have since been reintroduced to their historic range in the states of Botswana, Namibia, Swaziland and Zimbabwe. The northern white rhino is also protected as endangered but may be extinct in the wild, though its cousin, the southern white, has not required protection until now.