Motorists are being urged to avoid the A4119 between Coed Ely and Tonyrefail following an ongoing incident.
South Wales Police is currently at the scene, with the road closed in both directions between Ely Valley Community Sports Park and the Ely Valley Road roundabout.
Drivers are being advised to avoid the area and use alternative routes where possible while the incident is dealt with.
No further details about the nature of the incident have been released at this stage.
South Wales Police thanked motorists for their patience while the road remains closed.
