Two people are dead after a hostage situation that unfolded in the Central City area of Surrey overnight, and B.C.'s police watchdog has been called to investigate. 

The incident began when Mounties responded to a report of an armed man holding a woman hostage at a home on 100A Avenue Thursday night. The call triggered a tense standoff that lasted until morning and forced the evacuation of a number of nearby properties.

It ended with what the Independent Investigations Office said was an officer-involved shooting.

Few details have been confirmed, but the RCMP said officers made "multiple efforts" to engage with the suspect and hostage before members of the Emergency Response Team entered the home at around 7:30 a.m.

"A confrontation with the barricaded male ensued. The male sustained a fatal gunshot wound and was pronounced deceased at the scene," the Surrey RCMP detachment said in a news release.

Mounties said they found the woman seriously wounded inside the home, and that officers tried to provide emergency first aid treatment at the scene.

She was then rushed to hospital, where she succumbed to her injuries.

The RCMP later notified the IIO, which is tasked with investigating any police-involved incident that results in death or serious injury.

Members of the IIO arrived about two hours after the confrontation.

IIO chief civilian director Ron MacDonald confirmed police fired shots inside the property, but said investigators are still working to determine whether the alleged hostage-taker was struck by any of the bullets.

It's also unclear whether the suspect shot at police, and whether the hostage was injured by gunfire.

"We're not sure if the female was killed by shots. We're still trying to determine what caused her injuries and what led to her death," MacDonald told reporters Friday morning. "It's obviously very early in this investigation."

MacDonald said the man and woman knew each other, but couldn't say how.

CTV News has learned they had been in a long-term relationship and had a child together. The man was evicted from the Surrey home about two months ago, but the landlord allowed the woman to stay.