International wildlife groups say the critically endangered Javan rhinoceros has been wiped out in Vietnam, after the last surviving one was found dead there with its horn hacked off.

The manager of the World Wildlife Fund in the Mekong region says that with the animal's death, there is only one place on earth where about 50 of the Javan rhinos still live in the wild.

In a report Tuesday, the WWF blamed the extinction on ineffective protection of the creatures in Cat Tien National Park, where a small population of them was discovered in 1988.

But the park's director, Tran Van Thanh, said the rhinos had few defenses against human encroachment on their environment.

He said park workers had done their best to protect the rhinos.

Wildlife groups say the animal in Vietnam was likely killed by poachers for its horn. There is a huge demand for rhinoceros horn in several Asian countries, where it is used in traditional medicine.

WWF said other species nearing extinction in Vietnam include the tiger, Asian elephant and Siamese crocodile.