Police have closed the A1 in both directions in North Yorkshire after reports of a possible explosion in the Catterick Garrison area.
North Yorkshire Police say a report was received at 3am Saturday after an explosion was heard in the Catterick area. There are no reports of any injuries at this time.
Both slip roads to Catterick have also been closed and diversions have been put in place.
Motorists are advised to avoid the area at this time.
A police spokesman says this is a precautionary measure while police conduct their enquiries.
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