There are severe delays on the Prince of Wales bridge after a crash and spillage on the M4.
All traffic on the bridge was held from 16:30 BST on Friday, with long tailbacks for those trying to cross between England and Wales at rush hour.
The crash took place between junction 22 and junction 23. Lanes three in both directions are closed due to damage caused by the crash to the central reservation.
The official Severn Bridges X account [formerly Twitter] said that emergency services were in attendance.
Traffic monitoring service Inrix said: “Just before 16:30 all traffic was held.
“The closure has now been extended back to J21 to assist.”
Traffic is also congested on the opposite side of the motorway due to onlookers and trapped traffic has been allowed past the scene.
The incident is having an impact on traffic travelling northbound on the M5 from Portishead, while the M4 is congested back to the M32 for Bristol.
A diversion is in place, rerouting motorists via the M48 Severn Bridge.