A 21-year-old man was walking with a group on a busy downtown street Sunday afternoon when he was shot and seriously injured, Toronto police say.

Emergency crews responded to Queen Street West and Niagara Street, shortly before 5:30 p.m. after several reports of multiple gunshots heard.

Toronto police Insp. Stacey Davis said a group of people were walking on the sidewalk when gunfire erupted.

"That group dispersed, and our victim ran northbound on Manning (Avenue)," she said.

That was where police found an adult male suffering from a gunshot wound to the chest. He was rushed to a trauma centre with serious but non-life-threatening injuries.

Davis said the victim is now in stable condition.

The male suspect fled the scene on foot, Davis told reporters. He is described as Black, five-foot-eight with a slim build. His face was possibly covered with a bandana, and he was wearing all black clothing.

Police said the suspect had a black handgun.

Officers recovered three shell casings on the scene, Davis said.

When asked if the victim or the group was targeted, she said, "I can't actually say that for certain because our victim was walking in a group of individuals."

"Whether or not the shooter was shooting at the whole entire group or if our victim was actually targeted, I don't know that."

Davis described the incident as "disturbing" mainly because there were many people in the area at the time.

"Fortunately, there is only one victim, unlike yesterday," Davis said. She was referring to Saturday's quadruple shooting near Jane and Finch that critically injured an innocent 12-year-old boy.

"There were hundreds of people that were out walking around. There are still people walking around so clearly, it's a community safety issue. It's a policing issue."

She said several witnesses remained on the scene and had spoken to officers.

"However, that group, we're still trying to identify any of those individuals," Davis said.

"I understand this could be stressful for them. So, if they'd like to call Crime Stoppers to give us some information, that would be fantastic."

She is also appealing for businesses in the area to check their surveillance videos and contact police if they have information.

"The video is crucial," Davis said. "If we can track it down the street from where the victim came from, where the suspects came from, it would help us piece this together."