Vietnam's rare Javan rhinoceros was declared extinct in that area after poachers killed the last remaining animal in the country for its horns, the World Wildlife Fund said.

“Vietnam must see this loss as another warning sign of its looming wave of species extinctions,” Dr. Barney Long, WWF’s Asian species expert, said in a statement. “The single most important action that is needed to save remaining threatened species like tigers and elephants is protection.”

The country had been struggling to keep the population alive amid widespread poaching that the WWF said was the cause of many Asian rhino species being brought to the "brink of extinction."

The WWF said people in certain parts of Asia believe the horns, when ground down and dissolved in boiling water, help treat typhoid fever or even cancer, the WWF said, noting that there has been no scientific proof of that.

The group said trying to bring the species back into the area won't work.

“Reintroduction of the rhinoceros to Vietnam is not economically or practically feasible," WWF’s Asian Elephant and Rhino Program Coordinator Dr. Christy Williams said. "It is gone from Vietnam forever."

So now, the Javan rhino only exists in one area in the world, according to the WWF.

The group reported that there is one population of less than 50 animals in the Ujung Kulon National Park in Java, Indonesia. Now, workers will turn their attention there, working with anti-poaching patrols to hopefully keep the species from going extinct.

“For the Javan rhino, we now have to focus entirely on one site in Indonesia where strengthened protection is needed along with fast-tracking the proposed translocation and habitat management,” Long said.