Three people are dead and 12 more injured, including a 9-year-old girl in critical condition, after a mass shooting in Toronto's normally peaceful Greektown neighbourhood on Sunday night.

Toronto Police Chief Mark Saunders confirmed early Monday that one of the victims was a "young woman." The gunman who carried out the shooting also died at the scene.

The SIU later announced that a third person had died, but did not release any details about the victim. 

This is an extremely difficult event. Please report information to police. Paramedics are working extremely hard right now. This has been an unbelievable and tragic summer. https://t.co/RgGIdE2olr

— TO Paramedic Union (@416TPSUnit) July 23, 2018

Shots first rang out around 10 p.m. on Sunday evening near Danforth and Logan, according to Toronto Police.

A 29-year-old gunman whose motives are not yet known is said to have started firing a handgun at groups of people while walking along Danforth Avenue, which was bustling with restaurant and cafe patrons.

The gunman fired off 20 to 30 shots before fleeing the scene, according to witnesses. Police say they located the man nearby, on Bowden Street, and that shots were exchanged.

Chief Saunders says 14 people injured. One person has died, in addition to shooter. One young girl in critical. pic.twitter.com/G3AlQMqxah

— Wendy Gillis (@wendygillis) July 23, 2018

The man ran from police, according to the Special Investigations Unit, and was found dead on a Danforth Ave. sidewalk a short time later.

It is not yet known whether the suspect was killed by police or died by suicide.

My evening was nice until I heard shooting right out of my place on the danforth. So scary!! The gun violence in Toronto is crazy. pic.twitter.com/eNHLlUlp6r

— n💫 (@nsxoxoii) July 23, 2018

Footage shared by witnesses online during and after the incident paint a horrific picture of violence on the Danforth last night.

In one video, the gunman can actually be seen firing into what looks like a restaurant from the sidewalk.

Super raw & clear Video of #Toronto #Danforth shooter via @arilanise on Instagram. pic.twitter.com/6cbrDFHSOX

— Stilez (@stilez) July 23, 2018

People all over the world are expressing shock and sadness as news of the shooting spreads.

Many are pointing out much Toronto has already endured this year in light of April's deadly van attack, when a 25-year-old driver intentionally rammed into pedestrians along Yonge Street in North York, killing 10 people and injuring 16 more.

My thoughts are with everyone affected by the terrible tragedy on the Danforth last night in Toronto, and may the injured make a full recovery. The people of Toronto are strong, resilient and brave - and we’ll be there to support you through this difficult time.

— Justin Trudeau (@JustinTrudeau) July 23, 2018

"Tonight, a despicable act has been perpetrated on the Danforth in our city. On behalf of all Toronto residents, I am outraged that someone has unleashed such a terrible attack on our city and people innocently enjoying a Sunday evening," said Mayor John Tory in a statement.

"While our city will always be resilient in the face of such attacks, it does not mean such a cowardly act committed against our residents is any less painful," Tory continued. "This is an attack against innocent families and our entire city."

This is a tragedy and on behalf of all Toronto residents, we are extending our prayers to all the innocent people attacked tonight, their families and their friends.

— John Tory (@TorontosMayor) July 23, 2018

Danforth Avenue will be closed off completely between Carlaw and Broadview until at least noon on Monday, according to police, as TPS homicide detectives investigate the scene.

The hashtag #TorontoStrong is trending at number one on Twitter as of Monday morning, as it was for many days following the van attack in April.

This is a real tragedy for our city. My heart goes out to those who have been directly or indirectly impacted. #danforth #greektown #toronto pic.twitter.com/94e9j6jekx

— Christine Henry (@christine_henry) July 23, 2018

The Toronto Police Homicide Squad is asking any witnesses, residents and business owners who have any video or photos from Danforth and Logan to as far west as Broadview from last night to contact investigators at 416-808-5504.