Police confirm a 31-year-old woman has died following a series of alleged hit-and-run collisions in Cardiff on Friday afternoon.
Twelve other people have been injured - including at least seven children. Their conditions are currently unknown.
Police have arrested a 31-year-old man, who is being held at Cardiff Bay police station.
The woman has been named locally as Karina Menzies.
There have been at least four incidents across the western side of the city, at locations including Grand Avenue in Ely, Sloper Road, Crossways Road and Cowbridge Road West.
Rob Osborne has been following the investigation so far.
Other reports of the incident suggested the driver deliberately ploughed into parents walking home with young children after school.
"We had a customer in our shop who said the van mounted the curb like the driver wanted to run down young kids with their parents," a female shop worker in Grand Avenue, who did not want to be named, said.
"It was really frightening, people were screaming and shouting out, it was chaotic," she added.
One witness described the aftermath when two people were injured near the retail park in Leckwith.
"I was coming to get some tickets for the football, when I heard a van speeding" said Steven Christopher.
"I thought nothing of it, but then a girl said two women had been run over here".
– South Wales Police
Police in Cardiff are continuing to investigate a number of road traffic collisions in the Ely and Leckwith area of the city.
A 31-year-old man has been arrested in connection with the incident and a van has been seized.
Officers are currently in attendance at a number of locations including Crossways Road, Cowbridge Road West, Grand Avenue, and Sloper Road.
Motorists are advised to avoid the area.
The Welsh Ambulance Service has confirmed 12 other people have been taken to hospital - some with 'serious injuries'.
– Welsh Ambulance Service spokesperson
The Welsh Ambulance Service has responded to a number of road traffic collisions in the Ely and Leckwith areas of Cardiff this afternoon.
Eight emergency ambulances, five rapid response vehicles, four ambulance officers, two basics doctors and one Helimed attended several calls along Crossways Road, Cowbridge Road West, Grand Avenue, and Sloper Road.
Twelve casualties, including adults and children, have been taken to the University Hospital of Wales with various injuries, some serious.
The A&E Dept at UHW has been closed to anything other than casualties related to these incidents. In the meantime, the ambulance service is liaising with hospitals in the region including The Royal Gwent and The Royal Glamorgan to convey all other emergency patients.
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The injuries have consisted of fractures and some bone injuries, some of which are serious.
There was an outstanding effort by the staff in dealing with the specialist nature of the injuries, and all patients were dealt with appropriately.
I would like to pay tribute to the professionalism and the outstanding efforts of the staff when dealing with the situation and also obviously the other emergency services including the ambulances.
We reopened at 7pm this evening, and the hospital is open for business.