A man is believed to have received serious injuries after a lorry overturned and fell down an embankment near Llandeilo.
It is believed that the man has been airlifted to Morriston Hospital after the accident which occurred on the B4302 between Llandeilo and Talley at around 8.30am this morning.
Another person is understood to have been in the lorry but remains unclear if they have any injuries.
Fire crews from Llandeilo and Llandovery attended the scene.
The road is currently blocked in both directions between A40 junction in Llandeilo and the B4337 junction in Talley.
A Welsh Ambulance Service spokesperson said: "We were called at shortly after 8.40am to reports of a road traffic collision involving a lorry which had fallen down an embankment on the B4302 near Talley.
"The Wales Air Ambulance, an emergency ambulance and a rapid response vehicle attended the scene and a man was airlifted to Morriston Hospital in Swansea with serious injuries."
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