The number of sex offenders who live near schools stood at 5,098 as of this year, with 1,273 schools affected, data showed Wednesday.

According to the Ministry of Education, 4,270 sex offenders live near elementary schools while 635 and 191 sex offenders live near middle and high schools, respectively.

An average of 7 in 10 schools in Korea are located in a neighborhood where at one sex offender lives. And 102 schools are within a 1 km radius of the residences of more than 10 sex offenders.

Parents voiced concerns over the safety of students, who may be at risk of attacks from sex offenders, stressing that security should be strengthened in and around the schools.

In total, 1,671 schools were investigated under a safety program launched by the ministry in 2010 to prevent sex crimes by monitoring high-risk areas.