AURORA, Colo. No one was injured after a fire broke out at a condominium complex in Aurora Monday evening. According to Aurora Fire Rescue (AFR), firefighters were called out to the Appletree East Condominiums, located near the intersection of Parker Road and East Quincy Avenue, around 5 p.m. Monday. The department said multiple people called 911 after seeing smoke and flames. The callers also reported hearing breaking glass and popping wood due to the intense heat, according to AFR. Firefighters arrived and spotted heavy smoke and flames coming from a second-floor unit on the back side of the three-story building. The condo owners were not home when the fire broke out, so firefighters had to "force the door to the unit open" in order to extinguish the blaze, according to AFR. The fire department said the fire was contained to the unit and did not spread. No one was injured. Investigators are working to determine the cause and origin of the fire, according to AFR. AFR, citing the U.S. Fire Administration, said fatal fires in residential buildings are more common in the cooler months and peak in January.With below-zero temperatures expected this weekend, AFR is reminding the community to be alert and cautious when using space heaters.