KUNMING, Aug. 23 (Xinhua) -- Two slope collapses left four people missing in Fengshan Township, southwest China's Yunnan Province on Sunday, said local authorities.

The Ministry of Natural Resources activated a Level-IV geological disaster defense response for Yunnan at 2 p.m. on Sunday and dispatched a work team to the site to guide rescue efforts.

China has a four-tier emergency response system for geological disasters, with Level I being the most severe.