The 16-year-old boy who died after a stabbing at his Aberdeen school earlier today was a "very gentle, caring pupil, with lots of friends", his headteacher said on Wednesday.
The teenager, understood to be Bailey Gwynne, was taken to Aberdeen Royal Infirmary with serious injuries after the emergency services were called at about 1.30pm. He died a short while later.
Police have launched a murder investigation following the incident at Cults Academy. A 16-year-old has been detained by police to "help officers with their inquiries".
Bailey Gwynne died after a 'serious incident' at Cults Academy
Cults Academy head teacher Anna Muirhead said the school community has been left "totally devastated" and in shock.
Speaking to reporters tonight, Ms Muirhead said: "Pupils and staff are in a state of total shock. The boy involved was a very gentle, caring pupil, with a lot of friends.
"I think it's fair to say the whole school community is totally devastated. At the moment of course our thoughts are all with the boy's close family and his friends and what they must be going through at this tragic time."
Chief Inspector Graeme Mackie, of Aberdeen Police, said in a statement: "This is a shocking and extraordinary incident for Aberdeen and firstly our thoughts are with the family and friends of the boy who has sadly lost his life today.
"A full and thorough enquiry is underway and there will be a police presence in the area for the foreseeable future.
"We are working closely with the education authorities and wider community as I am sure this incident will be felt not only in Aberdeen but much further afield."
Dozens of people have paid tribute to the teenager.
Aberdeen City Council said in a statement: "It is with shock and sadness that we can confirm that a pupil of Cults Academy has died following an incident at the school earlier today.
"Our heartfelt sympathies are extended to the friends and family. We will be providing support to pupils, teachers, parents and the community in the coming days."