The teenage suspect in a knife attack at a Toronto-area high school is facing two additional charges, police said.

The 14-year-old, who cannot be named under the Youth Criminal Justice Act, was taken into custody last month after an incident in Pickering that injured nine people.

Durham Regional Police said a female student brought two knives to Dunbarton High School on Feb. 23. Officers said in a statement that she then "started attacking students in the hallways."

Six students and three staff members were injured.

The teen suspect initially faced 15 charges, including assault, possession of dangerous weapons and seven counts assault with a weapon.

On Tuesday, Durham police said in a statement that she has also been charged with two counts of assault with a weapon, bringing the total to 17 charges.

Anyone with information in the incident is asked to contact police at 1-888-579-1520, ext. 2528, or call Crime Stoppers anonymously at 1-800-222-8477 (TIPS).