A fast-burning fire destroyed half of a South Plainfield duplex home early Thursday, killing five members of a family and injuring four others, authorities said. Relatives and neighbors said the dead included several children.

The cause of the fire was not immediately known.

Fire Chief Thomas Scalera said the fire began early Thursday morning around 3:15 in the morning. The first floor of the destroyed portion of the home was engulfed in flames by the time firefighters arrived, making it difficult for them to quickly get access to the second story. The victims were found on the second floor of the home.

Residents stood outside of the one hundred and fifty year old home on that was home to two families, in awe of the devastation.

"It's absolutely horrendous that it should happen to anyone" said on resident referring to himself as Fred, adding "I have grandchildren and I don’t think I could survive something like that."

The duplex home, which sat on the corner of Clinton and Laurel Avenues, was once a former farmhouse referred to as Stockoff Farms.

Middlesex County Prosecutor Bruce Kaplan said authorities were working to confirm the identities of the victims and the causes of death. According to neighbors nine people lived in the home, including seven children and two adults. Family members and neighbors identified the grandmother who died in the blaze as 62 year old Ann Jefferson, they also stated that the mother of one of the children Natalie Jefferson was taken to the hospital. Witnesses saw three children being sent to the hospital.

He said police and the prosecutor’s office were investigating the cause of the fire.

Two volunteer firefighters received minor injuries when they were involved in a two-vehicle crash en route to the fire, Kaplan said.

(The Associated Press contributed to this story)