Police have begun a murder investigation after a 16-year-old boy who was stabbed by a pupil at a secondary school died of his injuries.

Officers have detained a boy, also aged 16, following the lunchtime attack at Cults Academy in the west of Aberdeen.

The incident took place within the school building and the injured boy was taken to Aberdeen Royal Infirmary with serious wounds.

The detained boy is helping officers with their inquiries and have begun a murder investigation.

Officers are still at the school following the attack.

Police in Aberdeen tweeted: "We can confirm that the Cults Academy incident is being treated as a murder investigation."

Chief inspector Graeme Mackie said: "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 inquiry has been launched 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."

An Aberdeen City Council spokeswoman said: "We are aware of a serious incident at Cults Academy today. Police are on site.

"Due to the nature of this incident, we will not be issuing further comment."

The school is described on its website as a six-year comprehensive serving the Lower Deeside area. It has about 1,050 pupils.