Avon and Somerset Police are appealing for witnesses and information following a serious coach crash near Brassknocker Hill at 11.30am this morning.
The incident involved a coach which left the viaduct and had nine passengers on board.
The coach left the road just before the Limpley Stoke Bridge and went down the embankment.
There were reports that three people were trapped and two seriously injured.
All three trapped have now been freed.
Both of the seriously injured trapped people have been released from the single-deck coach by firefighters using hydraulic cutting equipment.
A witness told the BBC that she could see the coach on its side: “The coach has overturned and fallen off the viaduct at the traffic lights on the A36.“
Two air ambulances and the Great Western Ambulance major incident unit attended the scene as well as ten fire appliances.
Roads remain closed in the area to allow investigations to take place and motorists are asked to remain patient, as this may have an impact on traffic in and around the area.
It is hoped the road could open later this afternoon.
Anyone who may have witnessed this collision is asked to call the Collision Investigation Unit on 101.