Butler County Coroner Wayne Garlock has said the children’s ages ranged from nine months to 17 years old.

He said the vehicles were likely to have hydroplaned on the wet roads and lost control.

Tropical Depression Claudette has caused flash flooding and tornadoes, destroying dozens of homes in Alabama.

Mr Garlock said a father and nine-month-old girl died in one of the cars.

The other eight victims were in a bus belonging to the Tallapoosa County Girls Ranch, a foster home for abandoned, neglected or abused girls. The youngest was four years old.

A bystander pulled the bus driver to safety and then tried to rescue the children, however the bus was already engulfed in smoke and flames, WTVC television reported.

“Our hearts are so heavy today. Our ranch family has suffered a great loss,” a post from the Alabama Sheriffs Youth Ranches, which manages the non-profit organisation, said on Facebook.

“As many of you may have heard, one of our ranch vehicles was involved in a multiple car accident yesterday afternoon. It is such a horrible tragedy and loss.”

Five other people were hurt in the crash, but none of their injuries were critical, Butler County Sheriff Danny Bond told Reuters news agency.

“It was a horrific scene,” he said separately to the Montgomery Advertiser. “It was the worst traffic accident I’ve witnessed in my life.”

Pictures from the scene show many burnt-out vehicles of all sizes, on the road and in the central reservation.

The National Transportation Safety Board was sending 10 investigators to the site.

A 24-year-old man and three-year-old boy were also killed in Alabama on Saturday when a tree fell on their house, just outside the city of Tuscaloosa.

A search is also underway for a man in Birmingham, Alabama who may have been swept away in flood waters.

Kay Ivey, Alabama’s governor tweeted that it was “a tragic day for our state”.

Tropical Depression Claudette brought torrential rain to much of northern Alabama, Louisiana and Georgia late on Saturday.

Shortly after making landfall in the morning, a tornado destroyed or badly damaged at least 50 homes in Escambia county, on the Florida border.

The storm was downgraded to a tropical depression, but forecasters warned heavy rain was likely to continue into Sunday, and flash flooding warnings are in place.