TWO air ambulances are at the scene of a crash involving two cars and a lorry.
A stretch of the A27 is closed between the Fishbourne roundabout and Stockbridge roundabout, near Chichester.
The crash happened at around 4.15pm.
There is currently miles of traffic in both directions due to the full road closure.
Sussex Police have asked people to avoid the area.
It is unclear how many people have been injured or how badly.
A spokeswoman for West Sussex Fire and Rescue Service said: "At 4.21pm we were called to a road traffic collision on the A27 eastbound, between Fishbourne and Stockbridge.
"Fire engines from Selsey and Bognor are at the scene, as well as a heavy rescue tender from Worthing. Hampshire and Isle of Wight Fire and Rescue Service are also providing support.
"The road is expected to be closed for some time, so we would ask the public to avoid the area for the time being."
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