Gwent Police issued the warning at 12.36am this morning, and urged drivers to avoid the Mountain Road area in Caerphilly. A spokesperson for Gwent Police said: "We're currently dealing with a road traffic collision on Mountain Road, Caerphilly. The crash was one of several incidents Gwent Police responded to over the weekend. Officers were called to Main Road Link in Brynmawr yesterday, August 8, and the road was closed for several hours, with diversions in place causing heavier traffic in the area than usual. Elsewhere, officers also dealt with a crash on the A469 between Llandbradach and Coed Y Brain roundabout.