Emergency services are at the scene of a "serious incident" on the in Gloucestershire and a crash on the Prince of Wales Bridge with traffic building throughout the region.
The multiple-vehicle collision took place near junction 23 of the M4 at around 3.55pm, involving two cars and two vans, which saw police and the ambulance service attend.
At around 6.20pm an incident also occurred on the M4 Prince of Wales Bridge. It is affecting traffic in both directions from junction 22 M49 to junction 23 M48. Wales Air Ambulance has also attended the incident.
A post on the National Highways website reads: "The M4 in South Gloucestershire/Monmouthshire is closed between J21 and J23 (Prince of Wales Bridge) due to a serious incident. Avon & Somerset Police and Gwent Police are on scene. Great Western Air Ambulance are also attending."
A statement from Gwent Police said: "Emergency services are dealing with a road traffic collision on the M4 between Junction 22 and Junction 23 on the Prince of Wales bridge. The road is closed in both directions."
The Daily Express has contacted the emergency services for comment.
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