VANCOUVER -- A fire that engulfed an abandoned building in New Westminster, B.C., Wednesday morning is under investigation.

Flames could be seen rising from the roof of the apartment building near Stewardson Way starting at 6 a.m. Heavy smoke could be seen from blocks away.

"The flames were coming out of the corner. They were the size of the trees at least," neighbour Matt McPherson told CTV News at the scene.

"I thought the trees were going to go up, but luckily they didn't… It was quite intense."

A building next door was evacuated due to the thickness of the smoke.

Firefighters used an aerial line and attacked the fire from all sides. They said the flames were stubborn and some areas ignited again and again.

At one point, part of the building collapsed.

Residents of the area say the building, which is slated for demolition, has been occupied by squatters for years, and that they've seen small fires inside often.

The fire chief wouldn't say whether the fire is considered suspicious, but said no one was injured.

Crews were able to keep the flames from damaging surrounding buildings, and are asking anyone who may have witnessed what started the fire to contact them or police.

With files from CTV News Vancouver's Regan Hasegawa in New Westminster