At least nine people, including five children, are dead after a fire broke out Monday morning at a home in South Memphis, according to fire officials.

Memphis Fire Department director Gina Sweat called the fire the worst within city limits since the 1920s.

Family members told WHBQ that the blaze claimed the lives of 11 people, including seven children between the ages of 3 and 16. One survivor, who was not home at the time, is the father of the seven children.

"Our whole city is in mourning," Memphis Mayor Jim Strickland said Monday at a news conference. "Take some time out … and pray for the family members remaining, to give them strength."

A majority of the victims died of smoke inhalation, according to MFD.

It was not clear whether the home had a working smoke detector. The home had security bars on its doors and windows, which might have hampered attempts to escape the flames.

The fire broke out around 1:30 a.m. at a home on the 1100 block of Severson Avenue. Investigators believe the fire started in the home's living room.

Medics rushed three children to Le Bonheur Children's Hospital, where they were listed in critical condition early Monday. At least one child was later pronounced dead.

The cause of the fire is under investigation.

MFD Lt. Wayne Cooke said that in his 27 years on the job, he has never seen this many victims in one incident.

A total of 10 people died in house fires across the state in all of 2015, according to the fire marshal.