Northamptonshire Police has shut Billing Brook Road next to Weston Favell Shopping Centre this afternoon after a child was reportedly hit by a vehicle.
Emergency services including Northamptonshire Police, East Midlands Ambulance Service (EMAS) and the Warwickshire & Northamptonshire Air Ambulance are now on the scene.
Billing Brook Road has been closed both ways, near the B&M store, AA Traffic is reporting.
A bus passenger, who didn't want to be named, told the Chronicle & Echo: "I was getting off the Tesco coach and there was a loud bang and I heard a woman screaming.
"It looked like a car had hit a little boy. She was carrying him and he had a large gash on the side of his head.
"One of the ladies on the bus was a nurse and took control of the situation."
A spokeswoman for EMAS said: “We received a call at 12:49 to an incident outside Weston Favell Centre.
"The caller reported a road traffic collision involving one patient and one vehicle.
"We sent a double-crewed ambulance to the scene and the Derbyshire, Leicestershire and Rutland Air Ambulance. One patient was taken to Queen’s Medical Centre via air ambulance.”
The air ambulance has just taken off.
More updates to follow.