A stretch of the the A40 near Monmouth is closed following a collision between a car and a pedestrian.
Officers from Gwent Police closed the A40 from the Dixton roundabout southbound near the Wyebridge lights at around 5pm on Thursday.
Motorists are being asked to avoid the area after reports of long queues on the A40 as emergency services deal with the incident.
South Wales Fire and Rescue Service and two ambulances from the Welsh Ambulance Service are also at the scene.
One person was injured and has been taken to the University Hospital of Wales in Cardiff. It is not clear how serious their injuries are.
A spokeswoman for Gwent Police said: "Emergency services are currently at the scene of a road traffic collision on the A40 Monmouth.
"We received a report of a collision involving a pedestrian and a car at around 5pm today.
"The A40 from the Dixton roundabout southbound to the Wyebridge lights is closed.
"Motorist are asked to avoid the area at this time. Members of the public are thanked for their patience and understanding."
