Police chief Mike Boyd gave a stern warning Monday that any attacks on his officers will not be tolerated after a series of incidents left some of his staff injured.

"I put everyone in our city on notice that the city of Edmonton is not going to tolerate this behaviour on our police officers or on any of our citizens," he said.

The warning comes after two separate swarming attacks on police officers in Edmonton within the last three days.

"I was outraged," he said.

An Edmonton police officer received a concussion and severe bruising to his face after he was attacked outside a north-end school Monday during a routine arrest.

The school resource officer was attacked shortly after he noticed a car "stunting" in the area of 114 Avenue and 68 Street during the noon hour, police said.

"He was just out supervising and this car was driving really recklessly so he was trying to stop them," student Jennifer Lawrence said.

As the officer went to approach the driver of the stunting car, who was talking to another person in a nearby vehicle outside of Eastglen high school, the driver pushed the officer.

The officers then usd pepper spray to get the man to the ground.

When the officer was arresting the driver, a passenger from the stunting car got out and kicked the officer in the head, knocking him unconscious.

Police said a teacher saw the attack and held down the suspect until more police could arrive. The suspects, believed to be former students of Eastglen high school, allegedly knew the officer.

Stunting is a police term for people creating excessive noise from their cars through tire squealing, hanging out of windows or yelling at pedestrians.

The officer was taken to hospital and treated for his injuries.

Two men, aged 18 and 20, and one woman have been arrested. Charges are pending.

A spokesperson for the Edmonton Police Service said the officer will be off for the rest of the week.

In a separate incident, two officers were swarmed by almost a dozen people in downtown Edmonton early Saturday morning after the tried to break up a fight between a group of people who had just left a bar on 107 St. and Jasper Ave.

The officers were swarmed by about a dozen people and attacked by three men.

Boyd showed a group of reporters the jacket an officer who was attacked on the weekend. The arm had been ripped off.

"Our police officers are not punching bags and neither are any of our citizens who are being attacked out there," Boyd said.

One officer received minor bruising from the attack.

With files from Deborah Shiry