COLORADO SPRINGS, Colo. -

People are back in their homes Friday after a scare in the middle of the night.

Firefighters spent hours battling flames engulfing an office building at 1409 Potter Drive, near Palmer Park and Academy Boulevard.

The fire was reported at 3:26 a.m. Firefighters were on the scene within several minutes but the fire was already out of control.

"The building was heavily involved when we arrived so we were behind the curve from the start," said Lt. Kriss Soppe with the Colorado Springs Fire Department.

It took 35 firefighters more than two hours to get an upper hand in the firefight. Firefighters announced the fire was under control at 5:45 a.m.

It was an alarming wake-up call for residents at Kelsea Court Apartments. They gathered in the parking lot near the burning building to keep an eye on the firethat was burning near their home.  

"It was just a big red fireball. Windows were popping and exploding. It was full of smoke, you could barely see in front of you," said Gilbert Alexander, the apartments' groundskeeper.

"It was smoked out, you could feel the heat. You know like, it was crazy," said apartment resident Reynel Garcia.

Garcia, Alexander and the apartments' manager alerted neighbors and asked them to evacuate temporarily until the fire was under control.

"I was more concerned about my neighbors and all the kids and people who live here," said Alexander about his decision to alert neighbors. "There was a lot of embers flying through the air and I know embers catch everything."

There are more than 250 people who live in the apartments.

"I started banging on everybody's doors so I did what I had to do to help everybody that lives here," said Garcia.

Garcia and his neighbors watched anxiously from the sidelines.

"This is what we own so, we don't have much, everybody who lives here," said Garcia. "This is what we have so pretty much if it burned this building down we would have nothing."

The early-morning sun showed the full extent of the damage. Neighbors were shocked by what little remained. The fire gutted most of the building's second floor. The roof collapsed in some areas. There was also extensive water damage to the first floor.

Authorities don't know what started the fire. Investigators are working to determine the cause. Investigators will also determine if the building is a total loss.

No one was injured in the fire.