The Mackenzie Sawmill in Surrey suffered extensive damage in a three-alarm blaze that broke out shortly after 1 a.m. PT Saturday.

It's the third fire in three years at the sawmill.

Deputy Surrey Fire Chief Karen Fry says fire crews initially responded to a report of "wires down."

"When we arrived here we were met with a fully involved mill structure fire. It was quickly raised from second to third alarm. It was pretty hard to get at," she said.

Fry says the mill's layout complicated the firefighting effort.

MacKenzie Sawmill fire

A firefighter pours water onto a major fire at the MacKenzie Sawmill early Saturday. Surrey's Deputy Fire Chief says the mill's layout complicated the firefighting effort. (CBC)

"It’s a lot of heavy timber within the building and a lot of machinery in the building," she said. "There wasn't a big fire load. There wasn’t a lot of wood or wood products in the mill today so it’s really just the machinery and the layout and the heavy timber within the mill."

Fire crews are on scene today, mopping up and putting out hot spots. An investigation is underway into the fire's cause, but Fry says it's too early to say whether it's suspicious.

No one was hurt. Fry says the mill wasn't in production and had been undergoing renovations.

In 2011, much of the mill was destroyed in a three-alarm blaze and in November 2010, the sawmill was temporarily closed after a smaller fire damaged equipment.

On mobile? Click here for a map showing the Mackenize Sawmill