A fire at a senior-living apartment building in a San Antonio suburb in the early hours of Sunday morning left five people dead and around a dozen injured, authorities confirmed.

Authorities said the fire broke out at around 6:30 Sunday morning at the Wedgewood Senior Living Center in Castle Hills. Five people lost their lives while 11 other residents were hospitalized.

The remaining 150 residents of the Wedgewood Senior Living Center were taken to a local high school. Many of the senior center's residents were still unaccounted for. It is still unclear how many of them had left the center for the holidays.

Around 48 units of firefighters were sent to douse the aggressive flames. They evacuated the apartment building by taking the elderly residents through windows with the help of truck ladders.

San Antonio Fire Chief Charles Hood said the fire had apparently started on the third floor of the building, which got fully damaged in the flames.

Speaking about the deadly fire calamity, Hood added, "After looking at the floors, it's amazing we did not have more loss of life."

Laura Jesse, a spokesperson for Bexar County Fire Marshall, also said that the cause of the three-alarm fire apparently originated on the third floor. An investigation to pin point the cause of the fire in still underway.