The Forest Protection Department in the south-central province released the creatures into the forest Thursday after taking care of two pygmy slow loris (Nycticebus pygmaeus), a northern pig-tailed macaque (Macaca leonine) and an Assam macaque (Macaca assamensis) for two years.

As they were weak when the department received them, they were restored to health in a park on the outskirts of Quy Nhon Town of Binh Dinh.

The two pygmy slow loris were handed over by the people of An Nhon Town and Quy Nhon Town, the northern pig-tailed macaque by the Trung Luong tourist area in Phu Cat District and the Assam macaque by residents of the same district.

"After they were taken care of and have their natural instincts restored, the four can now find food on their own, so we released them back into the wild," a department official said.

Both the pygmy slow loris and the northern pig-tailed macaque are categorized as vulnerable as per the International Union for Conservation of Nature (IUCN) Red List, while the Assam macaque is classified as near-threatened.

All of them face population decline due to either hunting or habitat degradation.

It is illegal to hunt, kill, possess, capture, transport, or trade protected animals in Vietnam, and penalties include 15 years in prison and fines of up to VND15 billion ($645,000), but poaching and wildlife trafficking remain significant problems.