Six men are being questioned after military documents with the names of more than 300 republicans were discovered in an Orange hall in Co Antrim. Photographs, addresses, telephone numbers and other personal details of republicans - all from south Armagh and the greater Belfast areas - were contained in the documents. The find was made last Saturday at Stonyford Orange Hall but details were released only yesterday.
The search was part of a security operation against dissident loyalists.
According to security sources, the documents had been in the possession of senior members of the Orange Volunteers, an anti-agreement paramilitary group linked to a series of pipe bomb attacks on Catholic families across the North.
The six being questioned come from Antrim, Glenavy and Stoneyford, Co Antrim, and Maghera in Co Derry.
At least two other people, one a former prison officer and the other a schoolteacher, were also held for a time before being freed without charge.
Sinn Fein claimed the find proved there was collusion between loyalist paramilitaries and the security forces.
A party Assembly member, Mr Conor Murphy, said: "This case raises a number of very serious issues.
"In the first instance what were British military documents doing in an Orange hall in the hands of loyalists? It underscores again the level of collusion which exists between loyalist death squads and the British army/RUC."
Mr Murphy called for an immediate explanation from the North's Security Minister, Mr Adam Ingram, and demanded that those whose details were contained in the documents be told what information was involved.
The arrests are part of an ongoing investigation into the activities of dissident loyalists. The military documents are still being examined by police.
A number of men have been charged and several weapons and home-made pipe bombs as well as ammunition recovered in police operations against the Orange Volunteers and another dissident group, the Red Hand Defenders.
The Northern Secretary, Mr Peter Mandelson, has written to the RUC Chief Constable, Sir Ronnie Flanagan, to congratulate his force on recent moves against dissident loyalists.