HOHHOT -- The death toll from a flash flood that swept through a campsite in the wilderness in North China's Inner Mongolia autonomous region has risen to 11, with one individual still missing, local emergency authorities said on Wednesday.

The disaster struck around 10 pm on Aug 16 in the upstream area of a river in Urad Rear Banner in Bayannur city, leaving 13 campers unaccounted for and four vehicles washed away.

One person has been rescued, and more than 1,600 rescuers have been dispatched to the site to search for the missing.

The Ministry of Emergency Management has demanded full-scale operations to locate the missing and sent a work team to guide operations. The ministry warned travelers during flood season to avoid undeveloped wilderness areas and exercise caution in geologically hazardous zones.