Firefighters battle 3-alarm apartment fire in NW Oklahoma City.

OKLAHOMA CITY (KFOR) - Fire crews responded to a three-alarm fire at an apartment complex Wednesday morning.

According to the Oklahoma City Fire Department, firefighters arrived at the complex near Wilshire Blvd. and Rockwell Ave. around 3 a.m.

Officials say the fire began in a downstairs unit and quickly spread to the rest of the building.

"We went inside and started fighting the fire and initially we got a quick knock down on it, but what had happened is it got into the pipe chases and spread to all units on there," said Batt Chief Jeff Chappell with OKCFD. "With this being what we call a mansard-style roof, or mansard-style walls, it spread throughout the whole building,".

A man nearby saw the flames and went over to the apartment complex to see what was wrong when he heard people yelling. He then jumped into action trying to help residents out of the building.

"I just thought, you know, it was just like a barbeque or something, but when I heard people yelling like 'Get out of the apartment! Get out of the apartment!', I ran over here and I was like 'Hey, call the fire department'," said Ethan Holloway. "I started calling the fire department and started knocking on people's doors, they didn't answer, I kicked the doors in."

One person received a minor burn to their foot and were treated by paramedics at the scene. Multiple residents have been displaced due to the fire.