An aircraft has crashed into several cars on the A27 during the Shoreham airshow, causing several casualties, Sussex Police said.
The road is closed in both directions for the rest of the day and drivers are being urged to avoid the area.
The aircraft involved was a Hawker Hunter, which failed to pull up after completing a loop.
This video was posted on YouTube shortly after the incident.
Sussex Police said: “Police are advising all drivers to avoid the A27 in the Shoreham area for rest of today, Saturday (22 August) after an aircraft has crashed.
“At about 1.20pm the aircraft hit several cars on the A27 just to the north of Shoreham Airport, where an air display is taking place. The aircraft ended up in a bush.
“There have been several casualties but we have no further information on these at the moment.
“The A27 has been closed in both directions and drivers are asked to avoid the area until further notice.”
Firefighters from Brighton and Hove were sent to support the emergency services operation at the scene.