Four men and a woman were arrested early this morning in Strabane, County Tyrone, in connection with attacks against nationalist members of local policing boards.
They are being questioned about a series of arson attacks and death threats against members of the 26 District Policing Boards.
Dissident republicans belonging to the breakaway 'Real IRA' have been blamed for the bulk of the threats and attacks but there have also been accusations that members of the mainstream IRA were responsible for the threats against policing board members in Cookstown, County Tyrone.
Sinn Fein's Mr Martin McGuinness yesterday denied mainstream republicans were involved in threatening Catholic members of the boards which liaise with local police chiefs on policing issues affecting their community.
Speaking after an arson attack on the car of one policing board member in Derry and just hours before the latest threat to Mr Denis Bradley, the Deputy Chairman of the main Policing Board, the Mid Ulster MP said there could be "no justification whatsoever for these attacks.
"I am absolutely of the view that there is no mainstream republican involvement in the intimidation of anyone. There are microgroups out there who have been active in this regard and our view on them is very, very clear they should stop," said McGuinness.
"In fact, they should go away and catch themselves on, and disband, and recognise that their strategy is not going to succeed in bringing about the type of policing changes that Sinn Fein wants."