Authorities in Dali city, part of the Dali Bai autonomous prefecture in Yunnan province, have launched an extensive search and rescue operation to find an 8-year-old boy who went missing on Saturday near a tea factory in the city's Dali town, according to a notice released by the city's publicity department on Sunday.

By Sunday afternoon, more than 300 personnel, two search dogs, four unmanned drones and five thermal imaging devices had been deployed to locate the child in the area, which features rugged terrain and dense vegetation, the notice said.

The number of personnel involved in the search continues to grow, and the search area is being expanded. Besides the location where the boy was last seen, efforts are also being concentrated in six key zones around it, with all available resources being deployed to locate him, it added.

The search and rescue operation is ongoing, local authorities said.

On Saturday at 1:43 pm, Dali city's public security bureau received a report that the boy had gone missing. In response, the city mobilized a coordinated search and rescue operation involving local police, fire rescue teams, forest firefighters, emergency services, the forestry and grassland administration, as well as volunteer groups of local civilian rescue teams. In an updated notice issued by the city government also on Sunday, residents have been encouraged to provide any information that could assist in locating the missing child.

The boy is about 1.2 meters tall with a slim build. At the time of his disappearance, he was wearing a blue and white striped shirt, dark jeans and carrying an orange backpack. He also has identification tags with his family's contact information. Anyone with potential information is encouraged to call the police. A reward will be offered for verified information, the notice said.

A resident surnamed Zhang from Dali city, who offered to help with the rescue, told China Daily on Monday: "Over 380 residents from Dali have created a WeChat group to organize civilian efforts for the rescue. At least 200 of them have participated in the rescue activities, either going up the mountain to look for the boy or organizing supplies needed on the mountain.

"As of around 4:30 pm on Monday, the volunteers have collectively walked over 600 kilometers. Everyone is very anxious, hoping to find the boy soon," he said.