SA police hunt for armed man

An armed man is at large after he allegedly pulled a gun on a couple in Adelaide and made off with their car.

The man and woman were sitting in their car in Prospect on Sunday morning when a man got out of a car behind them and stole the couple's car at gunpoint, police say.

Police gave chase but lost sight of the car at Hampstead Road.

They located the stolen vehicle but are yet to make any arrests.