Police north of Toronto say they've arrested a 30-year-old man who allegedly attacked kindergarten children at school and seriously injured one of them.

York Regional Police say they responded to an incident around 1 p.m. Wednesday at Our Lady of Good Counsel Catholic Elementary School in East Gwillimbury, Ont.

Sgt. Andy Pattenden says the accused left a nearby home and hopped a fence into a playground where kindergarten children were on recess.

Police allege he swung a curtain rod at the children, striking one of them before school staff and a Good Samaritan intervened, disarmed him and ushered the children inside the school.

They say paramedics took the five-year-old student to hospital with a serious injury.

The accused has been charged with aggravated assault, assault with a weapon, possession of a weapon for a dangerous purpose and common nuisance endangering life.