Over 1,300 firefighters and forest rangers were organized on May 1 to extinguish fires that spread across the border from Russia to Yimuhe forest, a primeval forest in the northern Greater Hinggan Mountains in Inner Mongolia.

Hundreds of firefighters extinguished fires in over 230 areas. A 2.8-kilometer-long separation belt was dug to prevent reignition.

Forest fires were eventually extinguished after an 18-hour battle by fire crews, according to regional fire authorities.

The cause of the fire is currently under investigation, and firefighters are still patrolling to clean fire-damaged sites to avoid re-ignition.

Strong winds, warm temperatures and dry forest conditions increase the risk of fires, according to local forest rangers.

Firefighters battle fires at Yimuhe forest, in the Greater Hinggan Mountains, Inner Mongolia autonomous region on May 1. [Photo/Xinhua]