Police are appealing for witnesses after a multi-vehicle crash that closed part of the M4 for most of yesterday.
The crash, which happened just before 9.30am between junctions 25 and 26 eastbound, involved a coach, a lorry and a car and was described as "serious" by police.
The coach driver and one of his passengers remain in hospital, where both are said to be stable.
More than ten other people were treated for minor injuries.
A Gwent Police spokesperson said: "Officers are appealing for anyone who may have witnessed the collision to call 101 quoting log 91 04/02/14. Those calling from outside the Gwent are should call 01633 838111."
The force added that enquiries are continuing into how the crash happened.