Authorities say six people have been killed in a fast-moving fire that roared through a single-family home in New Jersey's largest city.

The Essex County prosecutor's office says the blaze broke out at around 4 a.m. Sunday in Newark. The fire soon spread to another residence, and both homes were destroyed.

Prosecutors say the cause of the fire remains under investigation. The chief of detectives for the prosecutor's office tells the Star-Ledger of Newark that the fire doesn't appear to be suspicious.

Authorities say it appears some of the victims are related.