It is thought that dissident republicans may have been behind a shooting incident in Downpatrick, Co Down, this morning.
The police say they were in the area investigating the activities of dissident republicans at the time of the shooting.
The shots were fired, causing no injuries, at the Model Farm estate in Downpatrick shortly after 9am.
Police said a follow-up operation is underway and they have appealed for anyone with information to contact them.
The Sinn Féin assemblyman for South Down, Mick Murphy, also says a number of building sites in nearby Castlewellan, in south Down, have been damaged in petrol bomb attacks.
He is linking these attacks to attempts by dissident republicans to extort money from a local businessman.