People are being warned to look out for signs of illegal raves taking place.
This could include: the removal of locks from secured access points; vehicles, particularly panel vans or larger, driving off-road; groups of vehicles congregating in rural areas and convoys of vehicles
Country Land and Business Association (CLA) regional director Robin Edwards said: "We urge farmers and landowners to help the police by reporting any suspicious activity as early intervention and good local intelligence can prevent illegal events and organisers can be dealt with appropriately.
"Raves cause a great deal of disruption to local communities and often result in damage being caused to property and land."
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Police remain at the scene. They say there is no threat to public safety.
Tuesday afternoon's weather for the west of the region
Tuesday afternoon's weather for the east of the region