MIAMI: At least nine people died in a series of crashes on a northern Florida highway Sunday after a forest fire created a cloud of smoke that reduced visibility, officials said.

The "multiple crash" accidents occurred on the Interstate 75 highway in the early morning hours, said Lieutenant Pat Riordan of the Florida Highway Patrol, who noted that six to seven cars and four to five trucks were involved.

A total of 18 people were hospitalized after the pileup, according to a statement from Shands Hospital.

"We have now admitted six patients through our Level I Trauma Center and are treating 12 patients in the Emergency Department," the hospital said in a statement.

Riordan said the death toll was at least nine.

Officials said the cause of the fire was under investigation. Local media reported that there was evidence of a fire intentionally set.