KITCHENER -- The Ontario Fire Marshal is on scene investigating a fire at a Kitchener apartment building on Sunday morning.

All the residents of the building on Brybeck Crescent have been displaced as a result of the fire, and a few had to be rescued from their balconies.

Emergency crews were called to the four-storey building at 77 Brybeck Crescent around 6 a.m. Sunday.

Officials say the fire started in a unit on the third floor, but the cause has not yet been determined.

"There were people with sheets, bedsheets, trying to jump off from the thrid floor to go down and try and save themselves because there was so much smoke inside the hallways you couldn't even get down through the stairwells," said resident Stefan Jan. "I looked at my girlfriend and I told her to get dressed, let's get out of here. I saw people screaming as soon as I got out of the building and I saw all the smoke coming out."

Officials with the Ontario Fire Marshal's office said six people were injured in total. Of those, two had serious injuries and two had minor injuries. Four of the six people suffered from smoke inhalation.

"There was a lot of confusion and panic," Jan said. "Others, they were injured on the ground. Everyone wasn't sure what was going on at first."

In a news release, police said they don't believe the fire is suspicious.

All 59 residents of the approximately 30-unit building have been displaced and are being put up by Red Cross.

Investigators will remain on scene at the building until the residents are able to return.

Damage to the building is estimated to cost roughly $1 million.

"We're working with our engineers that we have on staff," said OFM investigator Jordan Froese. "As well, we have identified an area of origin within the unit of origin."