A total of 21 forest fires burst out and ravaged parts of Greater Khingan Range in nothern China's Inner Mongolia Autonomous Region between Wednesday and Thursday, leaving one forest service cadre dead, authorities said Friday.

Twenty of the fires have been put out, according to the regional major national forest management bureau of the Greater Khingan Range.

More than 4,500 people are battling the remaining fire that started Wednesday in a forest under the jurisdiction of the Jinhe Forestry Bureau.

Firefighters said that the steep slopes and lush vegetation were posing great challenges in fighting the fire and clearing the site.

Since June, around 30,000 thunders and lightnings have been monitored in the Inner Mongolia section of the Greater Khingan Range and its surrounding regions. Less rainfall and higher temperature have also increased the risk of fire.