A 14-year-old girl facing more than a dozen charges in connection with a knife attack at a high school in Pickering Tuesday that injured nine people made a court appearance Wednesday.

Dressed in a grey long-sleeved shirt, black yoga pants, and wearing evidence coverings over her shoes, the teen showed no emotion as she was formally charged with seven counts of assault with a weapon, six counts of assault causing bodily harm, one count of possession of weapons for a dangerous person, and one count of assault.

The girl, who cannot be identified under the provisions of the Youth Criminal Justice Act, is due to appear in youth court on March 1.

The charges stem from an incident that occurred at Dunbarton High School, on Sheppard Avenue near Whites Road, just before classes were set to begin yesterday morning.

According to Durham police, officers were called to the school at around 8:30 a.m. for reports that a female student armed with two knives was attacking students and staff members.

Nine people – three staff members and six students – suffered minor injuries. Four were taken to hospital for treatment.

The female student was subdued by quick-acting teachers who tackled her to the ground and held her until officers arrived, police said.

Police previously said they believe the students and staff injured in the incident were randomly selected.

The school was closed Tuesday but classes resumed on Wednesday morning.

Speaking to reporters at the school Wednesday, Durham District School Board Supt. John Legere said social workers were on hand today following the incident.

Attendance at the school today was very high, he added.

"Students and their families that we spoke to are feeling very supported," Legere said.

When asked about social media posts the suspect apparently made foreshadowing the attack, Legere said school officials are aware of online activity.

A link to a social media site belonging to the suspect – confirmed to CP24 through multiple sources – referenced a desire to carry out a knife attack at the school.

The posts, which were written last month, outlined the girl's apparent desire to commit a school shooting or stabbing and to commit suicide.

"The police are certainly aware of online activity," Legere said. "We will be cooperating with police fully."

The superintendent would not comment on reports that suggested the suspect had been bullied at the school.