A police officer was seriously injured in the head by a suspect, prompting a shooting involving law enforcement on Saturday morning in Vancouver, British Columbia.

Police shot a man after an officer was attacked with a weapon on Hastings Street, the Vancouver Police Department said in a statement.

Two officers were in their cruiser around 8 a.m. when a gunman approached and allegedly punched one of them through a window that was rolled down.

The individual was subsequently pursued, and shots were then fired by an officer. The 53-year-old suspect was taken to hospital with injuries, where he remains under observation for assaulting a police officer.

A policeman was also taken to a hospital to have his serious head injuries treated.

Another officer was slightly injured by a passerby after he arrived to help.

An investigation is underway with the Vancouver Police Department's Major Crimes Section and the British Columbia Office of Independent Investigations.