A serious road traffic collision has closed the A40 east and westbound between Carmarthen and St Clears.

Sion Rhydian, who witnessed the scene, said: "When I left, about an hour ago there were 10 plus police cars on the scene with more passing me on my way back to town.

"Roughly three fire engines, ambulances and also doctors and fire chiefs. Collision investigators also on scene.

"Queues were roughly mile long and back roads where people are trying to avoid the accident are also busy."

The collision occurred at around 8pm this evening.

PICTURE: Sion Rhydian

The road is likely to remain closed for some time.​

This story is updating.

UPDATE: The road Re-opened at around 3am. Word is still awaited on any casualties.