The suspect has barricaded himself inside a home after a stabbing left one person injured in Markham.
Emergency crews were called in a house on Briarwood Road, in the area of Warden and 16th Avenue, just before 9:30 p.m. for reports of a stabbing.
York Regional Police said a woman who resides in the home was stabbed. The victim has been rushed to a trauma centre.
Police said a man, who is also believed to be a resident of the home, is refusing to surrender.
Negotiators are on the scene trying to communicate with the suspect.
Police said it is not clear if the suspect and victim are known to each other.
More to come.
