UPDATE: 5.45pm

All lanes have now been re-opened after the crash this afternoon. The motorway was closed for around half an hour. Queueing traffic continues due to the accident, now on the hard shoulder on M4 eastbound between J29 A48(M) and J28 A48 / A467 Forge Road (Tredegar Park).

Congestion is stretching back to J30 on the M4 at Cardiff Gate and on the A48 Eastern Avenue to A4161 Southern Way (Llanedeyrn Interchange).

UPDATE: 5.16pm

Very slow traffic is reported on A48 eastbound between A4232 (Pontprennau) and M4 J28 / A467 Forge Road (Tredegar Park). The delays are due to the diversion away from the closure of the M4 between J30 (Cardiff Gate) and J28 (Tredegar Park).

UPDATE: 5.02pm

All casualties have now been freed from vehicles involved in the crash and are en-route to hospital.

UPDATE: 5.00pm

Fire crews have removed the roof from one vehicle and freed one person.

UPDATE: 4.54pm

Delays are reported on the Westbound side of the M4 as people slow to look at accident on the opposite carriageway on M4 between at J28.

UPDATE: 4.40pm

All of the M4 eastbound is closed between J30 A4232 (Cardiff Gate) and J28 following this afternoon's crash.

One person is trapped in one of the vehicles involved and two people have suspected back injuries South Wales Fire and Rescue Service say.

The A48(M) is also closed, to stop motorists joining the M4 at J29. A diversion is in place via the A4232 to the A48, then head East on the A48 to re-join the M4 at J28

Queueing traffic is reported due to the multi-vehicle crash A48 / A467 Forge Road (Tredegar Park).

Also affecting A48(M) Eastbound between J29A A48 Eastern Avenue (St Mellons) and M4 J29 The motorway has been closed to facilitate the emergency services, who are dealing with the accident.

UPDATE: 4.20pm

TWO lanes have been closed on the M4 eastbound between J29 and 28 this afternoon after a multi-vehicle accident.

Firecrews from Duffryn, Malpas and Ely are at the scene.