Gardai last night arrested 10 men, some of whom they believe to be closely associated with the "Real IRA".
Around 9:30 p.m. armed gardai raided a purpose-built underground bunker that had been modified as a shooting range and training ground. It is on farmland on a quiet road between Naul and Stamullen, on the Dublin-Meath border.
Gardai recovered an AK47 rifle, a pistol and a heavy machinegun as well as ammunition for all three. The area was sealed off and will be searched later this morning.
A number of the men arrested are known to gardai and believed to be associated with the "Real IRA". They are in custody under Section 30 of the Offences Against the State Act and were being held in Garda stations in Ashbourne, Co Meath; Balbriggan, Co Dublin; Drogheda, Co Louth; and Santry, in Dublin.
Some of them are believed to be close to the man who broke away from the Provisionals and formed the group called the "Real IRA", which planted the Omagh bomb.
Three of the men are from Dundalk, five are from the Dublin area, one is from Co Meath and another from Armagh.
Last night a senior garda said, "This is the result of ongoing intelligence gathering and is absolutely very significant." Armed gardai from the Emergency Response Unit and the Louth/Meath division took part in the raid.
Garda Supt John Farrelly said, "This is part of ongoing intensification by gardai in relation to dissident groups."