A fire broke out at a suburban Atlanta motel Thursday, killing five family members whose bodies were found in a bathtub and injuring at least six other people, authorities said.

The dead included two adults and three children, Georgia Insurance and Fire Commissioner John Oxendine said. The cause of the fire was not known.

Clayton County Fire Chief Alex Cohilas said six people were hospitalized, including three firefighters and two women and a man who were staying at the Budget Inn in Riverdale.

One of the people staying at the motel suffered severe burns and was being treated at Grady Memorial Hospital's burn unit, Oxendine said.

At least a dozen people were evacuated, Cohilas said.

Crews were searching for other victims in the partially collapsed motel, though firefighters believed they had accounted for everyone, Oxendine said.

It was not clear how many people were in the motel when the fire started, and all the records in the building were destroyed by the fire, said Lt. Billy Rice, a spokesman for the Clayton County Fire Department.

A firefighter passing by saw the flames and reported the blaze around 7:30 a.m., officials said.

Oxendine said the fire started on the second floor of the two-story motel.