The "nation is grieving" after the death of Detective Garda Colm Horkan, Taoiseach Leo Varadkar has said.
Mr Varadkar said the detective gave his life "protecting the community he had served with distinction and courage".
49-year-old Colm Horkan was shot dead while on duty in Castlerea in Co Roscommon last night, during what Garda Commissioner Drew Harris has described as a "random act".
Detective Garda Colm Horkan, who was shot dead in Castlerea last night. Image: An Garda SíochánaA man in his 40s has been arrested and is being held at the local Garda Station.
In a statement outside Government Buildings this afternoon, the Taoiseach said the country had lost a member of An Garda Síochana in the "most tragic of circumstances".
He said: "Colm gave his life protecting the community he had served with distinction and courage during his 24 years as a member of An Garda Síochana
"His story is the same as the thousands of men and women who wear the uniform - a story of courage, sacrifice and service.
"This tragedy is a heart-wrenching reminder of how much we owe our gardaí for the work they do all over the country. They protect and serve our citizens, our communities and our country - every day putting themselves on the frontline of crime prevention."
Detective Garda Horkan was an experienced detective from County Mayo, who had served as a garda for 24 years.
He is survived by his father, sister and four brothers.
Micheál Martin said there will be "much revulsion" all around the country at the fact that a garda's life has been taken "so cruelly and wilfully".
The president of the Garda Representative Association Jim Mulligan said Detective Horkan was an “experienced detective greatly respected by colleagues".
