Four Northern Ireland men arrested in Co Monaghan earlier this month were members of a Real IRA active service unit preparing to commit serious crime, the Special Criminal Court heard today.
Chief Superintendent Colm Rooney said he believed the men were about to commit "very serious crime either within or outside the State".
He opposed bail for three of the men and said he believed that if granted bail they would not turn up for their trial and would continue their activities in the Real IRA.
The four men were arrested after a Special Branch investigation into the activities of dissident republicans in Co Monaghan.
They are Garreth O' Connor (aged 23), of Bawnbrook Hill, Armagh City, Cathal Loughran (aged 26) of Friary Road, Clady, Co Armagh, Dominic Dynes (aged 30), of St Matthews Estate, Keady, Co Armagh and Aidan Grew (aged 46), of Benburb St, Blackwatertown, Co Armagh.
All four are charged with membership of an unlawful organisation styling itself the Irish Republic Army, otherwise Oglaigh na hEireann , otherwise the IRA on November 8.
Three of the four - O' Connor, Dynes and Grew - applied for bail but there was no application on behalf of Loughran.
Opposing bail, Chief Superintendent Rooney said that he believed all the accused were members of an illegal organisation known commonly as the Real IRA.
He said a garda investigation into the activities of the organisation had been going on in Co Monaghan.
The Chief Supt said none of the men lived permanently in the State and all had addresses in Co Armagh and he believed that if granted bail they would not turn up for their trial.
Detective Inspector John Gantley, of the Special Detective Unit, said members of his unit arrested the accused Dynes and Loughran after gardai intercepted a jeep and car on the old Armagh road outside Monaghan.
He said that later gardai were carrying out a search of a house in Co Monaghan when the accused - Grew and O' Connor - drove up to the gateway in a car.
When he asked Grew, who was driving the car, to turn off his engine, Grew reversed at speed and tried to get away.
Detective Inspector Gantley said he opened the door and called for assistance and Grew and O' Connor were arrested.
Refusing bail Mr Justice Diarmuid O' Donovan, presiding, said that the court accepted the unchallenged evidence of Chief Superintendent Rooney that the men would not turn up for trial of given bail.
All four men were remanded in custody until December 10.