HOHHOT, May 4 (Xinhua) -- Some 8,880 firefighters, including 3,090 forest police, are battling a fire that broke out on Tuesday in north China's Inner Mongolia Autonomous Region.

The fire has reportedly spread to 10,000 hectares in the Bilahe Beidahe forest in the Greater Hinggan Mountains on Wednesday.

Fire prevention headquarters said the blaze has been mostly brought under control and it had not expanded further as of 3 p.m.

However, strong wind and poor visibility have prevented planes from transporting fire fighters and food, and the soldiers have had to walk or take armored vehicles to move around.

An initial investigation found the fire was caused by illegal dumping of burning residue by a local furnace worker, who has been detained for further investigation.