WASHINGTON - At least nine people were killed overnight in pileups on a highway in the southern US state of Florida, due to hazy fog and smoke from a brush fire, local media reports said on Sunday.

At least 18 other people were hurt in the series of crashes, which occurred around 3: 40 am on the interstate I-75 in south of Gainesville, northern Florida. The wounded have been taken to Gainesville hospitals for treatment, the reports said.

Some of the cars were still smoldering on Sunday morning, as firefighters tried to put out the fires by spraying foam on them. Some of the vehicles smashed into a tractor-trailer. All three lanes on both sides of the highway were closed Sunday morning as investigators began probe into the actual causes of the pileups.

The Florida Highway Patrol (FHP) had briefly closed the highway before the crashes because of a hazy fog and heavy smoke from a marsh fire in the Paynes Prairie area, south of Gainesville. But the highway was reopened after the visibility improved a little.

FHP officer Patrick Riordan was quoted by local media as saying that this was the worst accident he has seen during his 27-year career with the FHP. He said that he did not know how soon the first crash occurred after the reopening of the I-75 interstate highway.