A fire has broken out on a national nature reserve in northwest China's Gansu Province, local authorities said Tuesday. The fire broke out on the Liancheng National Natural Reserve. Authorities do not yet know when and where the fire started, said Chen Wanzhi, office director of the Gansu Provincial Forest Fire Prevention Headquarters. Officials and firefighters are heading to the scene, Xinhua quoted Chen as saying. The Liancheng National Natural Reserve, located 140 km away from the provincial capital of Lanzhou, covers an area of 47,000 hectares between the Qilian Mountains and Loess Plateau.