Police have identified the man accused of stabbing four employees at a North Toronto office building, saying he was in the process of being fired when he attacked his superiors.

Police say Chuang "Ray" Li, 47, from Mississauga, Ont., is facing with three counts of attempted murder, four counts of aggravated assault and four counts of assault with a weapon.

Officers were called to the offices of Ceridian Canada just after 9:30 Wednesday morning after a man attacked four of his co-workers with a knife.

A man and woman in their 30s were rushed to hospital with life-threatening injuries and remain in critical condition. Two other men were also injured in the attack. Police say one man has been released from hospital while the other will remain in hospital overnight for observation.

According to Det. Dan Darnbrough, the two victims currently in critical condition were believed to be the attacker’s superiors and were in the process of firing him when they were stabbed.

Police say the two victims with less serious injuries allegedly tried to subdue the suspect during the attack.

In a statement released Wednesday afternoon, Ceridian said the attacker was a “former employee.”

“Our thoughts and prayers are with the victims and their families. As you might imagine, this is a very difficult time,” the company's chief executive officer David Ossip, and Dave MacKay said in a statement.

“Out of respect for the privacy of the individual and their family, we are not able to share or comment on the specifics of the individual’s condition but all four employees are being treated by medical experts at area hospitals.”

Employees working in the building described the chaos as emergency crews rushed to the scene.

“Guys were running in fairly quickly with their shotguns out, so it was pretty serious,” Steve Courier, an employee in the building, told CTV Toronto.

“I just saw two people being escorted to an ambulance. One had bandages around his head and the other had a torn T-shirt. There are a lot of police and EMS people moving around, but outside it is not much of a scene," Tony Bitonti, who works in the building next door, told CP24.

“I got some texts about what happened so I came outside, saw some people with blood on them and now there are trucks and paramedics all around," Razvan Nicolae, who also works next door, added.

Li was escorted out of the building by police soon after the incident and was seen with his hands covered in what looked to be blood.

He is scheduled to appear in a Toronto court on Thursday.

With files from The Canadian Press and CP24