The structural safety of a tunnel on the M4 has been assessed after a lorry burst into flames inside it.
The fire in the Brynglas tunnels at 8.30am on Tuesday led to widespread traffic jams.
After the blaze was extinguished structural engineers began looking at the bridge to assess the amount of damage that had been caused, a Welsh Government spokesman confirmed.
Later the road reopened for drivers with a contraflow system operating in the eastbound tunnel, the spokesman added.
South Wales Fire and Rescue said that the lorry driver was unharmed in the blaze and no other drivers were involved in the incident.
The Government spokesman said: "South Wales Fire and Rescue have now confirmed the fire is completely extinguished and they will soon be leaving the scene.
"Structural engineers will now enter the westbound tunnel to carry out an assessment of any damage caused."
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