Police are looking for three teenagers after a 14-year-old was stabbed outside his Birmingham school.
It is thought three youths were involved in the incident
The victim, who is believed to be from Winson Green, suffered stomach injuries outside Heartlands High School in Nechells and remains seriously ill.
He has undergone surgery at City Hospital following Friday's attack and his condition is not life-threatening.
The victim was playing football before the attack. Witnesses said they saw three youths running from the scene.
Det Ch Insp Mark Robinson said none of the three suspects attended the school.
He said: "I would stress that this is an isolated incident and at the moment all the intelligence would suggest it is just that."
The Police Federation has criticised penalties for carrying knives, describing them as "extremely soft".
The stabbing came a week after Kiyan Prince, 15, was knifed to death outside his London school.
A 16-year-old boy has been charged with his murder.
Police have been carrying out searches around the scene
The Police Federation has called for stronger sentencing of those caught carrying knives.
Paul Tonks from the federation said the existing penalties - with a maximum six months sentence for carrying a knife - were "extremely soft".
He said that normally "just a paltry fine" was given out.
Mr Tonks said of the knife-carrying culture: "I wonder whether it a fashion accessory.
"Knives are easy to get hold of. They are in everybody's house and everybody's kitchen."
"Society, and politicians in particular, need to appreciate this is a problem and it needs to be dealt with.