Five animals - two lions and three bears - were found abandoned in cages when Thai marines inspected a captured casino building immediately across the border from Trat province.
Thai wildlife officials were rescuing the animals.
Trat Marine Task Force soldiers inspected the now deserted casino building on the Cambodian side of the border, opposite Ban Tha Sen.
They found a pair of lions, two Asiatic black bears and one sun bear. All were locked in cages and were severely emaciated due to lack of food for a long time, the task force reported.
The Department of National Parks, Wildlife and Plant Conservation sent a veterinary team to the site on Monday to assess the animals’ condition and arrange for their immediate relocation.
The move was made difficult by the animals' weak condition.
The rescue operation was continuing on Tuesday.
The plan was to move the bears to Bang Lamung Wildlife Breeding Centre in Chon Buri and the lions to Khao Zon Wildlife Breeding Centre in Ratchaburi.
