Nine children and an adult were killed in a fiery multi-vehicle crash on an Alabama highway as heavy storms lashed the southeastern 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. "This was probably the most horrific accident in Butler County history," Sheriff Danny Bond told the al.com website.

He said at least two of the vehicles involved were 18-wheel trucks, and that four or five other people had suffered nonfatal injuries. Northbound and southbound traffic on busy Interstate 65 were halted for hours, but both had reopened by Sunday, the Alabama Law Enforcement Agency tweeted.

"Our hearts are heavy today. Our ranch has suffered great loss... Please send prayers our way," tweeted the Tallapoosa County Girls Ranch. The van in the accident was one of two bringing children, none older than 17, back from a Girls Ranch outing to nearby Gulf Shores, al.com reported. The other van was unscathed. The girls ranch serves as a foster home for children abandoned or from abusive families.