A fire inside a 13-story commercial and residential building in southern Taiwan has killed at least 46 people with dozens of others injured. Authorities said the fire broke out on Thursday morning in Kaohsiung city's Yancheng district.

Taiwan's official Central News Agency said fire trucks and rescue workers are already at the scene.  More than 377 rescue personnel are reportedly now attempting to put out the flames and search for survivors.

CNA said at least 46 people have been confirmed dead and around 41 people had to be taken to the nearest hospital to be treated for injuries. Initial reports had pegged the death toll to only around seven people. Fire officials later warned that the death toll could be much higher as the fire is still raging and there are still people trapped inside their apartments inside the building.

Fire officials said the blaze was "extremely fierce" and they were having a hard time putting it out. The fire also reportedly destroyed multiple floors of the building, which is estimated to be around 40-years-old. The bottom part of the building mostly contained shops and stores, while the rest of the building had apartments. The lower portion of the building was completely blackened by smoke and soot.

Most of those that were trapped were between the seventh and eleventh floors of the building. A total of 139 fire trucks and ambulances were sent to the building to help put out the flames and rescue survivors. So far, workers have rescued at least 62 people who were between the ages of eight and 83.

CNA reported that most the building's residents were senior citizens, some of which had physical disabilities that made it hard for them to escape the flames. Authorities have not yet determined the cause of the fire and an investigation is still underway.  Police are reportedly now reviewing surveillance footage leading up to the incident in an attempt to rule out human factors.

Some witnesses said they had heard a massive explosion before the fire erupted at around 3 a.m. local time. One woman was pleading for firefighters to rescue were elderly parents who had remained trapped inside the building.