Police are hunting a teenage boy after a teacher was stabbed at a Bradford school.
The 50-year-old male teacher at Dixons Kings Academy was taken to hospital with a stab wound after the attack, thought to have occurred as the school day was due to begin.
His condition was described by West Yorkshire Police as stable.
Officers are now searching for a 14-year-old boy, described as Asian with short dark hair. He was last seen wearing a blue uniform blazer.
Detective Superintendent Simon Atkinson, of the force's homicide and major enquiry team, described it as a "very serious incident", but insisted that they do not believe pupils or staff are at risk.
A statement on the school's website said it is working with the police to investigate and the academy is operating as normal.
Mr Atkinson said: "We are conducting inquiries 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.
"We would like to hear from anyone who witnessed the incident or knows the whereabouts of the suspect.
"At this stage we do not believe there is an ongoing risk to pupils or staff at the school. The rest of the school is continuing to operate as normal and local officers, including safer schools officers and members of the local area neighbourhood team, are currently at the school and are liaising closely with staff.
"We are also working closely with our partners in the local authorities to investigate the full circumstances of this incident, which will be the subject of a thorough investigation."
Police were called to the scene at around 8.55am by an ambulance crew responding to a report of a member of staff being stabbed.
The school's statement said: "There has been an incident at Dixons Kings Academy this morning. The police and the academy are working together to investigate the incident.
"There is currently no ongoing risk to pupils or staff at the school. The school is continuing to operate as normal and police officers, including safer schools officers, are on site to support staff and students."
It has given no further comment.
Kevin Courtney, deputy general secretary of the National Union of Teachers, said: "This is a dreadful incident. Our thoughts are with this teacher and his friends and family and with the students and colleagues at the school. It is always important to reflect on incidents like this to see if anything could have been done to prevent them, but to bear in mind that our schools are, in the main, places of calm and safety."
The attack comes a year after teacher Ann Maguire, 61, was stabbed to death by one of her pupils in a murder that shocked the country.
Will Cornick stabbed Mrs Maguire seven times from behind as she taught a Spanish class at Corpus Christi Catholic College in Leeds on April 28 last year.
Cornick, who was 15 at the time, boasted to his friends he was going to kill her and winked to his classmate before he launched the attack.
After the killing, he told psychiatrists he ''couldn't give a s***'' and added: ''Everything I've done is fine and dandy.''
The murder was branded a "monumental act of cowardice and evil" and Cornick was sentenced to a minimum of 20 years in prison before he is considered for release. But the judge, Mr Justice Coulson, warned him: ''It's quite possible that day may never come.''
Dixons Kings Academy was formerly the Kings Science Academy and joined the Dixons chain earlier this year.
Kings Science Academy, which was visited by Prime Minister David Cameron in 2012, was one of the first 24 free schools to open in 2011.
But it later hit the headlines after allegations of fraud emerged.
The school's founder and principal Sajid Hussain Raza was charged by the Crown Prosecution Service (CPS) with fraud and other offences relating to his involvement with the Kings Science Academy.
Raza was arrested last year following an investigation into the school.