West Yorkshire Police have launched a manhunt for a 14-year-old Asian boy who stabbed a male teacher at Dixons Kings Academy (08:55 BST).
The boy with short dark hair was last seen wearing a blue uniform blazer.
The 50-year-old male teacher was rushed to hospital immediately, his condition is described as stable now.
Detective Superintendent Simon Atkinson told the BBC: "We are conducting enquiries in the area to locate a suspect and I would like to reassure residents and staff that all necessary resources are being deployed to investigate this ongoing and clearly very serious incident."
He added there was no ongoing risk to pupils or staff at the school.
The school released a statement on its website saying it will continue to operate as normal and staff are working with police on its investigation.
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