Toronto police say officers are searching for multiple suspects after gunshots erupted inside Yorkdale Shopping Centre in North York on Thursday afternoon.

In a tweet sent shortly after 3 p.m., police said the mall was in the process of being evacuated after a gun was discharged somewhere on the east side the busy mall.

At a news conference, Toronto Police Service Superintendent Rob Johnson said the gunfire was a result of an altercation between two groups of men in the southeast corner of the mall, near the security office and a Starbucks.

“At some point, one of the individuals from one of the groups discharged a firearm at least twice – a handgun,” Johnson said. “Those individuals appear to have left the mall. They are not inside.”

Johnson said that there were at least three men in each group.

Officers have released suspect descriptions for two of the people involved in the altercation.

The first suspect has been described as a black male in his 20s wearing a black jacket with a hood and blue jeans. The second suspect is described as a male in his 20s with a skinny build, about five-foot-nine and carrying a black handgun.

Johnson said the suspects fled the area on foot through the southeast corner of the mall, towards the subway and GO station. Police do not know if the suspects got into a vehicle or used public transportation.

Paramedics say they assessed three patients for medical reasons, but there were no reported injuries as a result of a shooting.

Witness describes moment gunfire rung

A man said he was walking through the mall, near the Starbucks and Samsung stores, when he heard someone yell ‘hey’ and then saw someone run past him.

“And then the gun came out,” Frank Stanisci told CP24. “They shot repeatedly three times and I basically hightailed it out there.”

Stanisci said he returned to the scene because he felt like he should help. When he arrived he found a number of people on the ground, including an elderly woman, a number of children and a teenager in a wheelchair. He said he helped them off the floor and they ran into a store until police told them they could leave.

Stanisci said he gave a description of the suspects to the police.

Shoppers on lockdown

A large crowd of people accumulated outside the mall following the evacuation. According to reports on Twitter, some shoppers were on lockdown inside stores.

Some employees and shoppers at the mall initially believed the sound of the alarm was for a drill.

“We just heard screaming… We thought it was a joke,” a SilverCity employee told CP24. “I asked someone what happened and they said they didn’t know, so we had to get everyone out.”

One Twitter user wrote that they were locked inside the Rolex store for safety. Others said they saw people running and realized something was wrong.

"I was at Chapters with my mom when I saw everybody screaming and running out of the mall," one Twitter user, Felipe Lepecki, wrote. "Grabbed my mom and ran to our car. Really hope nobody got hurt."

A number of witnesses say they heard two or three gunshots ring out before mass panic took over the mall.

A store worker named Krystal told CP24 that she was working when her coworkers and customers started hearing gunshots.

“We locked the front and back of the store and then hid in our personal washroom with about 11 other people in a very small washroom. It was just crazy. Everyone started freaking out.”

Alexis Uiga was having coffee with her daughter Sam at at the time of the shooting. She said they heard a big bang, but thought it was a balloon popping.

“We looked over and we saw a bunch of panic and we heard a second shot,” Alexis said. “Then we had to find cover. We ran under a ledge. There was a little girl who was just clenched on to me, I have no idea who this little girl was. This mom and her son just falling over me, to take cover from the gunshots.”

Johnson said investigators are now sifting through video surveillance footage of the incident.

“We will be here until we make sure the place is safe and we have all available evidence,” he said.

The TTC says trains on Line 1 are not stopping at Yorkdale Station as a result of ongoing police activity.

Yorkdale issued a statement on Twitter saying that the shopping mall will be closed for the rest of the day “to allow police to investigate.”

“Yorkdale is secure and we are cooperating with police to safely evacuate the centre. We expect to open as scheduled tomorrow at 10 a.m.,” the tweet read.

Toronto Mayor John Tory issued a statement after the incident, thanking Toronto police and first responders for responding to the incident so quickly.

“Whether it is Yorkdale Mall or anyone else in Toronto, people should not have to worry about gun violence breaking out – at any time,” Tory said. “There are too many guns available to criminals in the city and I am determined to end that with the help of our police and our government partners. I am relieved that there are no reports of injuries from gunfire and I hope that remains true.”

Mayoral candidate Jennifer Keesmaat tweeted saying she has been following the situation and she was “hoping early reports that there are no injuries hold true.”

The investigation into the shooting is ongoing. Police are asking anyone who witnessed the shooting to call them at 416-808-3200.

Customers and employees who need to make arrangements to retrieve belongings can call Yorkdale Shopping Centre security at 416-256-5097.