P'Lu, 60, and Bun Kon, 37, have been freed from a long captive existence and released into the Yok Don National Park in the province.

Before the release, the two elephants were kept at the Ban Don Ecological Tourist Area in the province to take tourists around.

They were set free following an agreement between the tourist area and Animals Asia, a Hong Kong-based foundation that acts to end abusive animal practices in zoos and safari parks in Asia, and works closely with governing authorities to improve animal management and increase awareness of the welfare needs of captive animals.

Vu Duc Gioi, a senior staff at the national park, said that the two elephants were already weak, especially in their digestive capacity, and continued captivity and the activity of carrying tourists was a health risk.

The two elephants have been let to live by themselves in the protected forest of the national park. They will join other elephants that have also been released recently from tourism services at the park as well.

A year ago, Animals Asia and Yok Don Park signed an agreement under which the latter would convert its elephant tourism service into an elephant-friendly model.

The foundation would provide $65,000 in funds for the Yok Don area in return for the park letting the elephants live freely in its forest and look for food on their own.

With the release of the two elephants, the state-run Yok Don National Park is now home to six free elephants.

The animals are allowed to roam the forest, free of chains, while tourists can observe them in their natural habitat.

According to Animals Asia, elephants used in the tourism industry for riding typically endure conditions which greatly harm their welfare.

They undergo a process known as "the crush" during which they are confined and beaten with bullhooks; and when not giving rides, the animals are often chained, unable to express their natural behavior and kept in isolation.

In 2015, the elephant tourism industry made headlines in Vietnam when five elephants died, one after another, of exhaustion after being overworked.