The A35 is closed in west Dorset after a crash involving a lorry.
It happened in the area of Winterbourne Abbas sometime before 6.30pm.
The road is understood to be closed between Winterbourne Abbas and Bridport while recovery takes place.
It is not known if anyone is injured.
Bridport Fire Station said at 7pm: "We are currently dealing with a road traffic collision involving a lorry on the A35 between Bridport and Winterbourne Abbas. The road is closed and will be for some considerable time.
"Please avoid the area and find an alternative route."
Dorset Police said earlier: "We are currently at the scene of a road traffic collision on the A35 at Winterbourne Abbas near Dorchester.
"The road is closed between the junction with Winterbourne Steepleton and East Road Roundabout in Bridport to allow emergency services to safely deal with the incident.
"We would ask motorists to please seek alternative routes. Thank you for your patience and understanding."
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