The incident happened yesterday at Puvara Tour elephant camp which offers elephant rides for visitors in Muang district.
The 18-year-old male elephant, Phlai Meow, was on a forest tour with the Russian tourist and her daughter on its back. The animal was steered and guided by 60-year-old mahout Sook Submark, Bangkok Post quoting ASTV Manager, a popular Thai language newspaper.
The jumbo, who was reportedly showing highly aggressive behaviour, trampled Sook to death and ran into the wilds, carrying the tourists. Sook's body was found in a canal about 200 metres away from where he was killed, the report said.
Another mahout reportedly managed to jump from a slope on the elephant's neck and managed to control him. The two tourists safely jumped down from the elephant's back.