A man has been arrested on suspicion of firearms offences after items were found at an address on Dall Street in Burnley.
Officers attended the property to carry out a pre-planned warrant this morning (Tuesday) and a cordon has been established around the property.
A number of nearby properties have been evacuated as a precaution and a number of roads were closed and diversions put in place.
Supt Richard Robertshaw said: “We have evacuated a number of properties as a precautionary measure but there is not believed to be any immediate threat. We will endeavour to return people to their homes as soon as possible.”
The Explosives Ordnance Department are attending and a number of items have been recovered from the address.
A 30 year old man from Burnley has been arrested and is currently in custody.
An investigation is on-going.