A murder investigation has been launched after a 15-year-old boy was stabbed near a school in north west Leeds.
Emergency services were called to Town Street in Horsforth, near St Margaret's Primary School, just before 15:00 GMT on Tuesday, West Yorkshire Police said.
The boy, a former student at nearby Horsforth School, later died in hospital.
One teenage boy has been arrested in connection with the incident.
Initial reports suggested there had been two arrests.
Det Ch Insp Stacey Atkinson, said: "Our investigation is at an early stage and we are carrying out extensive enquiries to establish exactly what led to this needless loss of a young man's life.
"We understand the immense impact and huge shock a tragic incident of this nature will have on the community locally."
About 50 young people gathered at a candlelight vigil on Tuesday evening in Broadgate Lane, about half a mile from the police cordon.
People were hugging each other, with some wiping away tears, as they clustered around a bench covered in floral tributes.
A parent at the school, who did not wish to be named, said: "It's horrible. It's shocking because it's a nice area.
"You read about these things happening in London and you think it's dangerous to be a teenager there, but you don't think it would happen here.
"He probably went out this morning and they were expecting him to come home, and he's not there."
Pudsey, Horsforth and Aireborough MP Stuart Andrew said: "The terrible news in Horsforth today is deeply shocking and distressing and my heartfelt sympathy goes to the family of the victim.
"I cannot imagine how they will be feeling and my thoughts and prayers are with them at this dreadful time."
Mr Andrew said he was also thinking about the pupils, teachers and staff at Horsforth school who he said would be "devastated".
"The whole community will be stunned by this as the school is such a proud part of the town which is a peaceful and welcoming place," he added.
Earlier, in a message to parents, Paul Bell, head of Horsforth School, said: "You will be aware of a distressing incident in the community today, involving a former student of Horsforth School who was stabbed on St Margaret's Avenue."
Dr Bell said the school was aware of the distress and upset the incident had caused to students and staff and said the school would offer all the support it could to them.
The police cordon remained in place on Wednesday morning, with several bus routes diverted.
Councillor John Garvani, who represents the Horsforth ward on Leeds City Council, said: "It's a rare occurrence across the country, but when it happens on your own doorstep it's a real shock to the community.
"I've offered any help that I can - or ward colleagues can - give to the school."
The Labour councillor said counselling would be offered to affected pupils and staff.
He continued: "It must be a horrific incident to witness, it must be difficult to understand how they are feeling and I think there will be quite a few people in shock."