'School was hard, I exploded' says high schooler responsible for stabbing rampage

Police officers are seen outside a high school in Cheongju, North Chungcheong Province, on Monday, after a stabbing attack by one of the school's students. (Yonhap)

A high school student who carried out a stabbing attack that injured seven people on Monday told police he committed the crime out of frustration over difficulties at school.

"School life was difficult. I was holding it down, and I exploded," the 17-year-old suspect told investigators, according to officials at Heungdeok Police Station in Cheongju, North Chungcheong Province. Authorities said Tuesday they are seeking an arrest warrant for the student on charges of attempted murder.

Investigators believe that the suspect planned to attack anyone he encountered at school before taking his own life.

The attack occurred around 8 a.m. Monday during a conversation with a special education teacher. The student was designated to receive special education, but was enrolled in a regular class. He allegedly strangled the teacher and chased the victim with a knife, before seriously injuring three of the school staff, including the principal.

The suspect then fled the premise and attacked civilians outside the school, causing minor injuries to two people.

He later inflicted severe injuries on himself by jumping into a nearby reservoir, after which he was taken into custody.

Police found multiple weapons in the suspect's bag, which he allegedly used after school staff confiscated the knife from the initial attack. Authorities believe the attack was premeditated and are conducting forensic analysis of the suspect’s phone and laptop.