A major emergency response is underway after a serious early morning crash in South Australia.

Emergency services were called to Parawa Road, Torrens Vale, near Yankalilla on the Fleurieu Peninsula, about 3.45am on Saturday.

Ambulances, police officers, and Major Crash investigators are at the scene.

Parawa Road is closed in both directions between Range Road and Torrens Vale Road.

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Motorists are asked to avoid the area..

More to come