Toronto police are searching for four suspects who they said opened fire on three men in Regent Park Saturday evening, leaving one of them dead and the other two injured.

Officers were called to the area of Oak and Sumach streets, south of Gerrard Street East, just before 9 p.m. for a shooting.

When they arrived, they located three men, all in their 20s, suffering from gunshot wounds.

Insp. Michael Williams said one victim was pronounced at the scene while another victim who was shot in the torso was rushed to a trauma centre in life-threatening condition.

He said a third victim suffered gunshot wounds to his lower body and was also transported to a local hospital in non-life-threatening condition.

The homicide unit has been called and will take over the investigation.

"What I can tell you so far is it appears that four people dressed in dark clothing approached on foot, and all four of them apparently opened fire on these three men," Williams said.

He noted that approximately 50 shell casings were found at the scene.

When asked if the victims returned fire, Williams said it's still early in the investigation to determine that.

"I can't speculate at this point if there was an exchange of gunfire," he said.

Williams advised residents to expect heavy police presence in the area as officers talk to witnesses and canvass for videos.

"It's a highly-populated area. There's a playground just to the south of us. It was still 8:50 when this took place, so probably lots of people around -- very, very dangerous," he said.

"There are apartment buildings. There are low-rise townhouses all over the place, likely people on foot. We're hoping that someone captured something on video or maybe saw something from a balcony or maybe walking by and if they could come forward and contact our investigators from the homicide squad and 51 Division."

Police have not released any suspect information.

Coun. Kristyn Wong-Tam, who represents the area, said the shooting is gut-wrenching and urged anyone with information to contact police.

"I'm speaking to Toronto Police to better understanding what happened. City's Community Crisis Response Program will be in the community to support local residents affected," Wong-Tam tweeted after the incident.

"For the sake of all our children, we must put an end to gun violence in this city and country. Please hold Regent Park in your hearts tight tonight."