Murdered Garda Jerry McCabe
The killers of an Irish police officer were to be released as part of a deal to restore Northern Ireland's power-sharing executive last year, Gerry Adams has confirmed.
Detective Jerry McCabe was killed and another officer wounded during an attempted robbery at Adare in County Limerick in June 1996.
Four men were later convicted of his manslaughter and Sinn Fein has been calling for their release under the terms of the Good Friday Agreement.
Last Friday, sources told the BBC that the Irish Government agreed to the prison release as part of the deal to restore the devolved assembly at Stormont in October 2003.
The men are held in Castlerea prison in County Roscommon.
Speaking in Dublin on Tuesday, Mr Adams said: "Release of the Castlerea prisoners was part of an agreed sequence of statements and actions."
He told reporters: "I am very mindful that the release of the Castlerea prisoners is a sensitive issue and I am especially mindful of the plight of the McCabe family and Mrs McCabe.
Gerry Adams: "Release was part of agreed sequence"
"But you asked me if the release of prisoners was part of this agreed sequence. The answer is yes."
Speaking in the Irish Parliament later on Tuesday, Taoiseach Bertie Ahern said the releases were conditional on the IRA decommissioning and an end of paramilitarism.
He said the issue was not covered by the Good Friday Agreement.
"What emerged by April 2003 was a complex set of understandings involving a range of elements which would emerge as a sequence of agreed statements
and supporting actions - some by the governments, some by Sinn Fein, some by the IRA and some by unionists.
"This came very close to realisation at March 2003, but ultimately failed, as did a subsequent attempt at settlement last October - essentially involving the same range of elements."
He added: "Sinn Fein have made it clear that they are unable to convince the IRA leadership to take the necessary steps without the Castlerea prisoners situation being resolved.
"The government can consider the early release of these prisoners only in the context where the achievement of all other acts of completion as set out was assured.
"This means assurance of the complete ending of paramilitarism by the IRA and decommissioning."
Mr Ahern added: "If we ever want to get the end of the IRA... and that's what I want to do, then we are going to have to be brave, we are going to have to take some pain and we are going to get some gain."
On Monday, Irish Justice Minister Michael McDowell said: "While Provisional (IRA) paramilitarism is a reality there is no question of the government considering their release."
The release of the four men would have been seen as a significant concession to republicans.
A potential deal to move the Northern Ireland political process forward stalled over the issue of IRA weapons.
Unionists complained that not enough information had been provided on the IRA's third act of decommissioning.
The killing of Garda McCabe happened four months after the breakdown of the first IRA ceasefire in 1996 and initially the IRA denied any involvement.
It later admitted that individual members were involved - the IRA said "in contravention of its orders".
Since last October Sinn Fein have been demanding that the British and Irish Governments implement what was agreed.