Part of the A14 was shut outside a west Suffolk town due to a fire at a petrol station.
Emergency services were called to the incident at the Newmarket Rowley Mile garage at about 1.25pm on Sunday.
A spokesman for Cambridgeshire police said the eastbound carriageway was closed.
Pictures from the scene show two cars engulfed in flames, while black smoke has been sent into the sky.
Drivers were advised to avoid the area until "further notice".
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