GREAT FALLS, Mont. -

A judge has sentenced an 18-year-old Great Falls man accused of raping six girls between the ages of 12 and 14 to 60 years in Montana State Prison.

In handing down the sentence Wednesday, District Judge Greg Pinski disregard a plea agreement in which prosecutors recommended 10 years in prison and 35 years' probation for Kristian Underdahl.

The Great Falls Tribune reports Pinski called Underdahl a "serial rapist" and said there was a high likelihood he would find more victims given the opportunity.

Underahl says he feels bad for the people he's hurt and that sex is like a drug for him.

Underdahl pleaded guilty in March to one count of sexual intercourse without consent. Sentencing in a separate plea on a similar charge is pending before another judge.