HOHHOT, Aug. 4 -- Hundreds of armed policemen and firefighters are struggling to control fires in virgin forests in north China's Inner Mongolia, said local forestry authorities on Friday.Three fires had been detected by satellite data in the virgin forests north of the Greater Hinggan Mountain in northern Inner Mongolia Autonomous Region, the region's meteorological administration said.Two fires, one covering 2.87 square kilometers and the other 0.66 sq km, were near Ergune City, the administration said.Another fire was in a virgin forest north of Genhe City.Local forestry departments have confirmed that hundreds of people have been mobilized to fight the fires.The cause of the fires remains unclear.