There has been widespread condemnation of the murder of Detective Garda Adrian Donohoe in the course of an attempted armed robbery in Dundalk last night.
President Michael D Higgins said he was “deeply shocked” to learn of the murder.
"This is a dreadful crime and all Irish people will be truly appalled by it," he said.
“I wish to extend my deepest sympathy to the late Garda’s family and all to all of his colleagues. I have already conveyed my condolences to the Garda Commissioner.”
Taoiseach Enda Kenny said he learned of the shooting with “deep shock and great sadness”.
“This was an outrageous act of cold blooded violence that has left a family without a husband and father and the Garda Siochana without a brave and valued member,” Mr Kenny said.
“On behalf of the Government and of the people I would like to express my condolences to Adrian’s wife and children and to all his extended family at this unbearably sad time.”
Mr Kenny also expressed his sympathies to Garda Commissioner Martin Callinan and “all of Adrian’s colleagues in An Garda Siochána who I know will spare no effort in bringing to justice those responsible for this appalling crime”.
Speaking at Garda Headquarters early this morning, Mr Callinan said he was “deeply saddened” to hear of the death of his colleague.
“At this time my thoughts and prayers and those of the entire force are with the family, friends and close colleagues of Adrian.”
Tánaiste Eamon Gilmore said the killing of a garda in the line of duty was "shocking" and a "heinous criminal act". He said his thoughts were with the family, colleagues and friends of the deceased garda.
Minister for Social Protection Joan Burton said the shooting dead of the garda was "really an attack on Irish society" and was a "sobering" event.
Fianna Fáil Leader Micheál Martin said the "cowardly act of violence" had caused "revulsion and rage in homes across the country today".
"It represents a direct assault on our society and our sense of community. It deserves a response on the same scale. No stone should be left unturned and no resource denied to the gardaí in their pursuit and prosecution of those responsible and all associated with them."
Fine Gael TD for Cork East and chair of the Oireachtas justice committee, David Stanton, described the murder as “horrific”.
“I would like to express my horror and anger at the murder of Detective Garda Adrian Donohoe who was going about his duties protecting the people of this country. He was gunned down with warning as he sought to prevent a robbery,” Mr Stanton said.
He expressed his deepest sympathies to Det Garda Donohoe’s family and colleagues.
“Every effort will be made to bring these killers to justice. Detective Donohoe was working on behalf of the Irish people and any attack on the gardai is an attack on every man, woman and child in this country.”
Louth Fine Gael TD Peter Fitzpatrick also condemned the murder.
"I have known Detective Donohoe for many years. I played football with him and managed his local GAA team. He was a gentle giant whose wife and three children meant the world to him. As a volunteer in his local community, he was loved and respected by all who knew him," he said.
"This horrific and senseless murder has deeply shocked the community, his family and colleagues and everyone who knew him."
Mr Fitzpatrick said gardaí and the PSNI were "working closely together to track down these cowardly murderers and every effort will be made to ensure that these four criminals will be found and brought to justice".
Louth Fianna Fáil TD Seamus Kirk said Det Garda Donohoe "was a highly respected member of our community and was very much involved in local life. His senseless death has left all of us mourning".
Archbishop of Armagh: Dr Richard Clarke said the first thoughts must be with Det Garda Donohoe's wife Caroline and his family.
"Those of us of religious faith will hold them in our prayers. The callous taking of any human life is a vicious insult against humanity and against the God who gives us life. In addition, the murder of a servant of society in pursuit of his or her duties is an assault on society itself and each one of us. Let us never become indifferent to the reality that we have all been attacked by this deed."
He said his Church of Ireland colleague, Archbishop of Dublin Dr Michael Jackson joined with him in expressing "on behalf of the whole Church of Ireland our absolute censure of this action and our sincere sympathy to Detective Garda Donohoe’s family".