A massive fire seriously damaged an apartment complex under construction and did some minor damage to several nearby homes in North Portland early Wednesday morning.

Portland Fire & Rescue responded to the scene at North Killingsworth Street and North Minnesota Avenue around 4:19 a.m. Neighbors reported hearing windows shattering and seeing flames and the construction site and called 911.

Firefighters said the fire had been burning for about 20 minutes before they arrived. The three-story building had been no more than a wooden frame, which caused it to burn quickly.

Crews were forced to evacuate surrounding homes and businesses due to the extent of the fire. Power lines and polls were also damaged, knocking out power in the area.

Two aerial fire trucks were brought in to help contain the blaze. Crews had to pour about 60,000 gallons of water on the building to help douse flames.

Several businesses flooded, including Portland Ice Cream Company next door. Owner Michael Shillingford said friends called him to tell him the building next to his business was on fire.

"I sped down here. I was a little bit worried but it looks like Portland Fire Bureau did and great job in saving my building," said Shillingford.

Crews believe the building was unoccupied and no injuries have been reported.

Several structures nearby suffered minor damage, include a rooftop five houses down from the initial blaze. Crews are continuously checking neighboring houses for flare-ups.

PF&R at scene of a 2nd alarm residential fire at N Killingsworth and Minnesota. PIO enroute. Media staging on I-5 overpass on Killingsworth.— Portland Fire&Rescue (@PDXFire) August 17, 2016
Pouring water on fire near I5 Killingsworth!#fire #fox12 pic.twitter.com/AJEp6YZ75Q— Marilyn Deutsch (@marilyndeutsch) August 17, 2016

Fire officials are investigating the cause of the fire.

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