Ten fire engines have been battling a caravan fire which threatens to destroy an adjacent thatched property.
The fire service was called just after 12pm to a fire involving a caravan on the A357 by the Glue Hill Junction near Sturminster Newton.
The caravan is believed to contain gas cylinders.
Fire engines and from Sherborne, Sturminster Newton, Wincanton, Shaftesbury, Gillingham, Blandford and an aerial appliance from Yeovil were all sent to the scene to try to bring the fire under control.
The fire is now known to have started in the caravan, which has been destroyed, but the cause of the fire is not known.
The blaze quickly spread to a nearby tree which in turn set fire to the corner of a thatch roof on an adjacent property.
A spokesman from Dorset and Wiltshire Fire and Rescue said: "We have surrounded the fire and are currently doing a lot of protection work with both water and foam to the thatched property to try and prevent it catching.
"What we don't know is whether the fire has already got underneath so at the moment we are treating it as a thatch fire and trying to stop it in its tracks."
A spokesman for DWFRS said crews were cutting in a 'thatch break' into the roof.
"We are cutting into the thatch from the gable end and stripping the thatch back to ensure there is no smouldering or sign of fire underneath.
"The problem with thatch is it can burn from inside so you can't see it. We've worked hard to stop the spread and although there is damage to the roof it could have been a lot worse."
Police are also on the scene and have shut the A357 in both directions to allow the fire service to carry out their work.
Access to and from Glue Hill is also restricted.
Traffic is queueing on the B3092 Bridge Street between B3091 Old Market Hill and A357 Newton Hill.
The road closures are also causing delays through Sturminster Newton.
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