At least three people, including an elderly woman with Alzheimer’s disease and her two adult children, were killed in a raging house fire early Sunday morning in Bayside, Queens, according to neighbors and firefighters.

Firefighters responded to 20th Street between 33rd and 34th Avenues around 2:40 a.m. after receiving reports of a fire, the FDNY said.

Three people were killed in the blaze, fire officials said.

Neighbors told The Post early Sunday that the family consisted of a mother, who was in her 90s and had Alzheimer’s; her son; and a daughter who had Down Syndrome.

“They’re all dead. It was a mother and her two children,” the family’s next-door neighbor Desmond Brennan, 81, said.

According to Brennan, both of the children were likely in their 50s.

“It was just black smoke pouring out of the house. I ran out and I saw them bringing one body out and laying it on the ground. They were doing CPR chest compressions but they couldn’t save [them],” he said, adding that the bodies were “covered in black” soot.

“They’ve lived here for a long long time over 50 years. I unfortunately I saw their bodies being brought out,” Brennan said.

“The family has had such a tough time already. I kept looking for their dog. I never saw them bring the dog out,” he added.

Fire officials confirmed there was a dog killed, and that the fire was under control in about an hour. 

At least 106 firefighters and EMS personnel responded to the fire, which started in the home’s basement and, which was put out just after 4 a.m.

Crews found two unconscious people in a first-floor bedroom and another victim in the basement, Chief of Dept. John Esposito said during a news conference.

A neighbor told The Post the son’s badly burned body remained in the basement after the fire had been put out. 

“Our policy, our procedure is that when it’s a confirmed DOA that they’re left in place and it’s the medical examiner that’s charged with taking care of that,” Esposito said when asked about the victim whose body remained in the home. 

“No hydrant problems thankfully at this fire. The hydrants were clear. But we do have three people who lost their lives in a fire. By all accounts that’s unacceptable to me. We’re going to do everything at the FDNY to make sure fire deaths stay low. We certainly are thinking about the family is that are affected by this,” Fire Commissioner Robert Tucker said. 

FDNY officials have not yet released the names of the deceased.

Fire Marshalls are on the scene investigating.