Singapore  - A Singapore serial molester who sexually assaulted girls as young as 9 has to serve 32 years in jail after a court dismissed his appeal against his sentence, a media report said Monday.

From April 2007 to July last year, Huang Shiyou, 23, a full-time national serviceman, trailed girls up to the age of 14 into lifts, threatened them with a knife and then forced them to secluded spots where he assaulted them.

"The systematic and serial nature of his offences demonstrate a propensity to reoffend, and the key consideration for the court is on prevention," the online edition of the Straits Times newspaper quoted the appeal judge as saying.

Huang pleaded guilty to five charges of aggravated molestation, sexual assault and attempted rape and was first sentenced in April. (dpa)