UPDATE: The road has now reopened.
A section of the A470 between Newbridge-on-Wye and Rhayader is closed following a crash early this morning.
Traffic Wales has said the A470 is closed in both directions between Doldowlod to Newbridge-on-Wye.
The road is closed at the junction with the A4081, which is also closed, Dyfed-Powys Police has said.
Police have advised the public to avoid the area.