A herd of wild Asian elephants attacked two patrollers with the local forestry department in Yunnan province on Saturday, leaving one dead and the other injured.

The victim was on patrol with his partner in Lancang county, Pu'er, when they came upon a herd of 18 elephants in a heavy fog, according to local authorities.

After receiving the emergency call from the patrollers, Lancang forestry station reported the case to its border forestry station in Xishuangbanna Dai autonomous prefecture, which is more experienced in dealing with wild elephants.

With joint efforts from the local government and public security department, the body of the victim was found by a drone. The case is under investigation.

It is believed this same herd is responsible for the deaths of four people in the prefecture last year, according to the forestry department.

Yunnan is China's only habitat for wild Asian elephants, and the wild elephant population has grown there from 170 in the 1970s to about 300 now, thanks to animal conservation and protection efforts.

The elephant population has grown by two to three annually in recent years, according to Chen Mingyong, a life sciences professor at Yunnan University.

An adult Asian elephant usually weighs between 3 to 5 metric tons and consumes 150 to 200 kilograms of food each day.

Chen said the growing number of wild elephants has resulted in more conflicts between local people and the pachyderms as they seek more food and a larger territory.

"The elephant habitat area in the prefecture expanded from seven counties last year to nine," he said. "While they are not predators, wild elephants are known to be territorial, and will attack humans if they feel threatened."

As the major habitat of wild Asian elephants, Xishuangbanna has witnessed more than 153,000 cases involving conflicts between wild animals and local people from 1991 to 2010, according to the local forestry bureau.

A total of 33 people died and 165 were injured in the conflicts, most of which involved elephants trampling farmland, resulting in a financial loss of 270 million yuan ($39.8 million).

To solve the problem, the local forestry department has introduced drones to monitor the elephants' activities and send alerts to local residents since June 2016.

Moreover, elephant feeding and watering stations have also been built in some nature reserves to ease tensions between local farmers and wild elephants.