Hundreds of firefighters are battling a fire in China's largest forest in the Greater Hinggan Mountains. The fire broke out at 12:15 p.m. Tuesday in the Beidahe forest in north China's Inner Mongolia Autonomous Region, said regional fire authorities. More than 700 police have been mobilized to extinguish the blaze. Strong winds and mountainous terrain are making their work difficult. The cause of the fire is unknown. A fire broke out Sunday in another forest in the area. It has been put out and cleanup is underway.