Irish reaction: The Government last night condemned the brutal murder of the British hostage victim, Mr Ken Bigley, who was granted an Irish passport just days ago.
The President, Mrs McAleese, said she too was "greatly shocked and saddened" by Mr Bigley's death.
"Despite the best efforts of all those who endeavoured to secure his safe release from captivity, Mr Bigley has been cruelly taken from his loved ones," Mrs McAlleese said in a statement.
"My deepest sympathies are with the Bigley family who have conducted themselves with immense dignity during a period of unimaginable distress and heartache. I join with the people of Ireland today in extending my most sincere condolences to the family on their profound loss."
The Taoiseach, Mr Ahern, speaking in Vietnam where he is attending the Asia-Europe summit meeting, said: "This callous murder of an innocent man is a most shocking and brutal outrage. The perpetrators have shown a total lack of mercy and humanity and in doing so have reached new depths of barbarism.
"I am profoundly saddened by this murder of an Irish citizen," Mr Ahern added, "and my deepest sympathy and the sympathy of the Irish people are with his mother, Elizabeth, his wife and family at this sad time."
The Tánaiste, Ms Harney, said the killing of Mr Bigley was "a depraved and barbaric act".
The Government became involved in the Bigley crisis on September 23rd, following a public plea by his brother Paul. During an interview with RTÉ radio's News at One, Mr Paul Bigley disclosed that his mother has been born in Ticknock, Co Dublin, and had emigrated to Liverpool.
This prompted the then Minister for Foreign Affairs, Mr Brian Cowen, to raise the matter with British Foreign Secretary, Mr Jack Straw.
Following a request for a statement the following day by the Arabic news channel, al-Jazeera, Mr Ahern appealed for Mr Bigley's release and safe return.
A similar plea was made by Mr Michael D. Higgins of the Labour Party who offered to go to Iraq.
The publicity about Mr Bigley caused thousands of Irish people to contact al-Jazeera by e-mail to plead for the engineer's release.
Immediately after he replaced Mr Cowen in Iveagh House, the new Minister for Foreign Affairs, Mr Dermot Ahern, contacted the Jordanian Foreign Minister and the Iranian Embassy in Dublin.
The Government's involvement went on to a new level on Tuesday when the Minister granted an Irish passport, but to no avail.
Last night, Mr Higgins condemned Mr Bigley's murder. "This is an appalling act that will advance no cause or interest and must be condemned without reservation.
"The only hopeful consequence of this and other similar atrocities would be if the international community would now engage in a positive and sustained way to remove the sources of conflict in the Middle East and help find a path to peace."