KUNMING, Aug. 7-- A primary school teacher suspected of raping several girls in southwest China's Yunnan Province has been detained, local authorities said Friday.

The male teacher, surnamed Lu, was detained at Mohei Primary School in Muzhuo Township, Zhenxiong County in Zhaotong City on Tuesday, according to a statement from the county's publicity office.

Police in Muzhuo Township received a report on July 29 from a villager who claimed that his daughter had been raped by the teacher, the statement said.

The case caused public concern through online media reports, which said several girls in the school were raped by the teacher. All of the victims are children who live with relatives while their parents work in the city, known as "left-behind" children.

Investigation into the case is ongoing.

The instance is one of several sexual assaults reported in primary schools across the country in recent years, prompting concerns for the safety of "left-behind" children in rural areas.

China has more than 60 million rural children who are left to relatives, usually grandparents. According to a 2013 report released by the All-China Women's Federation, nearly 3.4 percent of the children live alone.