SEOUL, Sept. 14 (Yonhap) -- Violent crimes by adolescents surged nearly 50 percent over the past two years, mainly driven by young rapists, a report showed Wednesday.

A total of 3,428 adolescents were probed last year as suspects of murder, robbery, rape and arson cases, according to the report by the National Police Agency.

The number was up 48 percent from 2,322 youth suspects recorded in 2008, it said.

The rapid growth of adolescent crimes over the past few years was driven mainly by juvenile rapists, according to the report. The country saw the number of youth committing rapes increase by 337 percent to 2,029 last year from two years earlier. 

Juvenile murderers rose to 23 from 19 during the cited period while youth committing robbery and arson decreased by 25 percent and 24 percent respectively, the police report noted. 

Meanwhile, the total number of young criminals, which includes minor offenders as well as felons, reached 94,862 for 2010, falling 23 percent from two years earlier, the report showed. That indicates the total number of youth crimes is decreasing, but the crimes are showing deepening ferociousness.

Of the overall youth crimes last year, theft accounted for 39 percent, with minor violence representing 25.9 percent. Serious crimes such as murder, robbery, rape and arson made up 3.6 percent of the total, according to the report.