More than 1,000 people are struggling to extinguish a forest fire that has been raging in a rural area of southwest China's Yunnan Province since noon on Wednesday, according to an announcement on Thursday.

The blaze has spread across more than 27 hectares of forest on a mountain near the village of Luohe in Yuxi city, a spokesman with the local forest fire control headquarters said.

It was triggered by splashing coke from a blast furnace of a nearby steel plant, the spokesman said.

Firemen, troops, police officers and local residents have been mobilized to put out the flames, but steep hills and dense vegetation have added difficulties to the operation, he added.