HOHHOT - Four college students in north China's Inner Mongolia Autonomous Region drowned when they were organizing a picnic near a local river, a local government official said Sunday.

Twelve students from the College of Erdos of Inner Mongolia University went on a picnic on Saturday near the Ulan Murin River in the city of Erdos, a city official said.

One student accidentally fell into the river while the students were playing near the riverside. Another five also fell into the water while attempting to rescue the first one.

Two were rescued by police and firefighters. Four others drowned and their bodies were retrieved, the official said.

In May, two drowning cases involving students occurred in central China's Henan Province and south China's Guangdong Province, respectively, claiming the lives of nine primary and middle school students.