At least seven people have died after a dense “super fog” caused a huge 158-car pile-up near New Orleans.

Twenty-five people were injured in the crash on Interstate 55 in St John the Baptist Parish, said police, who warned the death toll could rise.

Thick fog and fumes from multiple marsh fires mingled to reduce visibility for drivers commuting on Monday.

Watch this video from the scene, showing a trail of burnt-out cars and mangled metal.

Read more: ‘Super fog’ kills seven in 158-car US pile-up