The sanctuary in Luang Prabang, the ancient capital of Laos, is run by Free the Bears, an Australian wildlife conservation group that works with local communities and governments in Asia to rescue and protect the endangered Asiatic Black Bear, commonly known as the moon bear, and the equally at risk smaller sun bear native to Southeast Asia.

The group's CEO Matt Hunt said the sanctuary was considering expanding its play, housing and veterinary facilities as it has never hosted so many bears, or ones so young, before.

The cubs are now being bottle fed, and will need to stay in the sanctuary for several months until they are big enough to survive on their own, he added.

The cubs were seen playfully running at the sanctuary and swimming in a small pond.

"It's probably the single largest-ever rescue of endangered bear cubs worldwide," he told Reuters.

Laos police rescued the cubs in late March during a raid on a home owned by a Chinese national, Hunt said. The neighbours alerted the police, after hearing the cubs crying. By the time the police were able to extract them, one of the cubs had died, he added.

"They are extremely young, seemingly purchased illegally from hunters across Northern Lao ... most likely to try and establish a bear bile farm," Hunt said.

Bear bile farming involves extracting bile from the gallbladders of living bears for use in traditional Chinese medicine. The practice is legal in China, but outlawed in Laos, Vietnam and Cambodia, among other countries.

(Reporting by Napat Wesshasartar, writing by Chayut Setboonsarng, Edited by Miral Fahmy)

By Napat Wesshasartar