SHIRLEY, N.Y. — A fast-moving fire that killed a Long Island mother and her three young children spread before she could wake them up and carry them to safety, authorities said Saturday.

The blaze, at a small home in Shirley, about 60 miles east of New York City, was reported at about 10:15 p.m. Friday.

Suffolk County police identified the victims as Jennifer McCusker, 41, her son Aidan Tarbell, 7, and her 2-year-old twins, Brendan and Ava Jane Mistretta.

McCusker was found holding one of the twins in a bedroom, police said. She appeared to have been overcome by smoke, said police detective Lt. Jack Fitzpatrick. The other twin lay in a crib nearby. The 7-year-old died in his bed, police said.

Authorities said at a news conference Saturday that the fire appeared to have started in the living room of the single-story home. The cause, though, wasn't immediately clear.

One neighbor told authorities the house seemed fine one minute, then was suddenly engulfed in flame 15 minutes later.

"The front door of the house was open, the screen door was open and the front of the house was on fire," Fitzpatrick said.

Two men on the block, one an emergency medical technician and the other a volunteer firefighter, tried to enter the house but couldn't get inside because of the smoke and heat, authorities said.

The children had different fathers. One lived in the house but wasn't home at the time of the fire, police said.

Autopsies on the victims were being performed by the county medical examiner.

"We're devastated. The whole block is devastated. They are 2 and 7 years old. They didn't even get a chance at life yet," said neighbor Sharon Browning.