The Garda Commissioner has met with the family of Detective Garda Colm Horkan to express his condolences.
The 49 year old was shot dead while on duty in Castlerea, Co. Roscommon last night.
A man in his 40s has been arrested and is being held at the local Garda Station.
The Taoiseach has offered his deepest sympathies to the family and friends of Detective Garda Colm Horkan.
Leo Varadkar says the nation is grieving following his death.
The President Michael D Higgins paid tribute, saying:
"As President of Ireland I wish to express my deepest sympathy to the family and friends of the Garda, and to all those who have been affected by this tragedy.
"An Garda Síochána play a crucial role in our communities and this loss of life is traumatic for our society as a whole."
Justice Minister Charlie Flanagan offered his sympathy to Detective Horkan’s family and gardaí all around the country.
"We reflect on what it is to be a member of An Garda Síochána.
"It is a difficult career. They are charged with protecting us all from harm on a 24/7 basis and they put themselves in harm’s way in order to ensure our protection.
"Think about over the last weeks, during the COVID emergency, when the Gardaí worked to assist communities urban and rural and particularly helping the vulnerable and now we have a situation where, once again sadly, we are waking up to the tragic loss of life of an active member of the Garda service.
"My sympathy to all gardaí at this particular time."
Garda Commissioner Drew Harris says:
"Today is a terrible reminder of the significant sacrifices, including the ultimate sacrifice, that Gardaí make to keep people save."
The president of the Garda Representative Association Jim Mulligan says:
"Our brave colleague died as result of injuries sustained when he was responding to an incident."
