A primary school pupil allegedly stabbed and killed a Grade 7 pupil while "playing" at a Peddie school on Thursday, Eastern Cape police said.
Police spokesperson Captain Khaya Tonjeni said the two boys were on the Mpekweni Primary School premises at about 09:00 when the incident took place.
"While they were playing, the suspect, 15, stabbed the deceased in the upper body. He was immediately taken to the nearby clinic for medical attention, where he was certified dead on arrival," Tonjeni said.
"The circumstances surrounding the incident will form part of the investigation."
He said the 15-year-old pupil was arrested and was being "processed in terms of the Child Justice Act".
Acting Eastern Cape police commissioner, Major General Andre Swart, said police visits and random searches would be intensified, "even to primary schools".