The Tánaiste has warned the "Colombia Three" that the Government is determined to explore all options open to it to ensure Ireland plays "its full part in the fight against international terrorism".
In a lengthy statement issued in her role as acting Minister for Justice Ms Harney confirmed that no formal extradition request had been received from the Colombian government. She said the Government was considering whether the men could serve their sentences in the Republic.
Bogota has already called for the three men to be arrested and sent back to Bogota to serve their 17½-year jail terms for training Farc guerillas, an offence that they deny.
Yesterday the Colombian president Álvaro Uribe said regardless of whether there was an extradition treaty or not between Ireland and Colombia, the "war on terror" worldwide means there should be a collaboration between countries.
"In a world as globalised as this, countries should not be able to deny extradition."
"The Irish Government can't be negligent, the can't bury their heads in the sand," he added.
The men appeared back in Ireland on Thursday after months on the run after an appeal court in Colombia overturned their earlier acquittal. Their return to Ireland spared a crisis in the peace process and prompted the Taoiseach to cut short his holidays in Co Kerry.
In the latest move by the Government, today, Ms Harney said Niall Connolly, James Monaghan and Martin McCauley were "no friends of the peace process." But she said she "would not and could not" interfere with issues that are the responsibility of the Garda or the Director of Public Prosecutions.
She said the Government was considering the question of the three men serving their sentences in Ireland in the event of extradition proceedings being unsuccessful. She cited the Transfer of Execution of Sentences Bill 2003, currently at Report Stage in Dáil Éireann, as a possible means of achieving this.
Colombian president Álvaro Uribe
"It is important that the three persons involved and those who have expressed exultation at their return to this country should not under-estimate the Government's determination to explore all the options open to it to ensure that Ireland continues to play its full part in the fight against international terrorism," Ms Harney said.
Earlier, Minister of State at the Department of Justice Brian Lenihan said he was "absolutely certain" the men's reappearance had not been part of any discussions between the Government and Sinn Féin in the lead up to the IRA's statement ending it's armed campaign.
The Minster also criticised Gerry Adams for welcoming the men, Martin McCauley, Niall Connolly and Jim Monaghan, home.
"Mr Adams welcomed home these three individuals from Colombia and of course their arrival at this point in the peace process is deeply unhelpful.
"While he may have to welcome them home to a particular constituency, he has the wider constituency of all of the Irish people who are interested in seeing progress in the peace process.
"The last time these gentlemen appeared in Colombia and came to public notice, they caused a major disruption in the peace process," he said.
Meanwhile, the Progressive Democrats TD Noel Grealish said the men should serve out the 17-year prison terms imposed by Colombian courts last December.
Mr Grealish said: "The three men are convicted of criminal activity or wrongdoing in Colombia, and I think they should serve their term in prison here."