A Greater Manchester Police spokesperson said "Officers were called to a school on Reddish Vale Road in Stockport at around 3:10pm Monday 10 February following reports of a person with a knife on the premises.
A spokesperson for Stockport Borough Council said: "We are aware of the distressing incident that took place at Reddish Vale School earlier today and we understand the concerns being shared by parents, students, and the wider community.
Chilling moment schoolboy, 12, ‘stalks playground brandishing HUGE knife in front of pupils’ CHILLING footage has captured a schoolboy allegedly stalking a playground while brandishing a large knife in front of terrified pupils.
"I've told the school that I won't be sending my daughter to school until I know what precautions have been put in place to keep our children safe.".
Chief Inspector John Picton, of GMP's Stockport Neighbourhood Policing Team, said: "Whilst we do believe that this was an isolated incident, additional patrols have been deployed to the area to offer reassurance to the local community.