Five people were killed in a Sunday morning fire that broke out at a senior living apartment building in San Antonio, Texas, KENS 5 reported.  

Hundreds of firefighters arrived at the Wedgwood Senior Living Apartments in response to the 3-alarm blaze that broke out at around 6 a.m. About 75 residents had to be carried out of windows or down ladders from the burning building located in San Antonio's Castle Hills suburb, the station reported.

Officials have not yet identified those killed in the fire. At least 10 people were injured, with one listed in critical condition at a local hospital, the San Antonio Fire Department told the San Antonio Express-News.

Investigators are determining the cause of the fire, which is believed to have started on the third floor. Doors on that floor were burnt to a crisp and the entire floor was destroyed, SAFD Chief Charles Hood told KENS 5.

One third-floor resident said the sprinklers did not go off on her floor when the fire broke out.

"I tried to open the door but it was jammed," an unnamed 87-year-old resident told the Express-News. "I went to a window and opened it a little and began yelling for help.

"I was scared," she continued, "the heat was so intense that the blinds began melting in the room. I yelled and yelled, the door was stuck and finally somebody broke it in."

Other residents said the sprinklers went off on other floors in the 11-story building. 

Those evacuated were taken to the nearby Churchill High School cafeteria where family members were told to go find their relatives. Other residents are being put up in the hotel Courtyard Marriott, the newspaper reported.

Castle Hill officials are not sure when residents can return to their homes.