Nine children and an adult were killed in a fiery multi-vehicle crash on an Alabama highway as heavy storms lashed the southern US state, a county coroner confirmed Sunday.

Saturday's crash on an interstate highway near the city of Greenville involved at least 15 vehicles and may have been caused by aquaplaning under heavy rains, Butler County coroner Wayne Garlock told AFP.

The dead included a father and daughter in an SUV, and eight occupants of a van carrying children from a county-run "girls' ranch" that included foster children, local media reported.