The number of young girls allegedly sexually abused by a security guard at a city kindergarten now stands at 11, police said yesterday.

Another four girls, aged between six and seven, were added to the seven alleged victims previously reported at Tongxing Kindergarten in Minhang District.

And officers warned the number is likely to increase further as more parents, who used to be reluctant to report abuse as they feared the exposure would be bad for their child's future, will come forward.

Police said some victims' parents were even unaware of what happened.

Others are still waiting for medical reports from hospitals.

An emergency meeting was held yesterday by the Minhang District Education Bureau, which regulates all 15 private kindergartens and 85 daycare centers in the district. It said that from now on at least one teacher must patrol classrooms when children are taking noon naps.

In the past, the bureau said private-owned kindergartens and daycare centers must hire professional guards from large companies, and offered to subsidize one appointment.

The series of sexual assaults is alleged to have started last year.

Guard Han Baosi, a 34-year-old Jiangxi Province native and cousin of the kindergarten owner, is said to have slipped into classrooms while children were taking a nap and abused girls, taking photographs and movies with his cell phone.

Meanwhile, although local kindergartens are required to hire professional security guards from legal companies, many private-owned kindergartens - often catering for the children of non-local families in suburban areas - hire cheaper, unlicensed guards. These are unlikely to have been vetted.

At private-owned Xiangtai Kindergarten, also in Minhang District, the only stipulations for a security guard was that he had to be more than 168 centimeters tall and have no tattoos. No details of qualifications or a clean criminal record were requested.

"It's too expensive for us to hire a professional guard," said the director of a Baoshan private-owned kindergarten, surnamed Zhou.

Zhou said it cost only 300 yuan (US$46.4) to 500 to train a migrant worker as a security guard, and their salary would be less that 1,500 yuan per month. A professional guard is usually paid between 3,000 yuan to 4,000 yuan per month.

The Minhang education bureau said it would not close kindergartens hiring unqualified guards as the children would have no place to go.