Building partially collapses after large fire in downtown Hamilton, Ont.

A vacant commercial building in downtown Hamilton has partially collapsed after a fire ripped through the space Saturday morning.

At around 6 a.m., crews were alerted about a fire at a four-storey century building at 206 King Street West.

Meanwhile, Cunliffe said a fire broke out on a condo balcony nearby at 20 George Street and is believed to have started because of embers from the building fire.

"Fire crews were very quick to respond and we got that fire out with minimal damage to the balcony."

No injuries to civilians or firefighters have been reported.

A nearby resident, who identified himself as Marwan, lives across from the building and said he woke up to the smell of smoke.

"I went to my balcony, I looked left and there was a huge fire at this building. I saw the police everywhere and ambulance and it was really a huge building so I don't know how it (happened). Because of the smoke I couldn't see anything. It was terrible," he said. 

Cunliffe said it is unknown where the fire started in the building and what caused it.

"At this point, this fire is still deep seated. We will be on scene for the better part of the day, if not into the evening. And we continue to have structural collapse," Cunliffe said.

Crews said smoke from the fire migrated east and across the mountain.

Residents are being advised to keep their windows closed.

The Office of the Fire Marshal is aware about the blaze but it is unknown if they will investigate.

As of Saturday afternoon, crews said the majority of the fire is out but they remain on scene putting out hot spots and cleaning up debris.

Road closures in the area are expected to stay in place for the remainder of the day.