© Photograph: Kim Haughton for the Guardian
Sinn Fein president Gerry Adams said he was deeply shocked by the detective's murder.
Four men fled after botched hold-up on a cash delivery to a credit union near Dundalk.
A detective has died after he was shot during a botched hold-up outside the town of Dundalk in the Republic of Ireland.
The Garda officer, who was in his 40s, was among colleagues who were escorting a cash delivery to a credit union in the County Louth town, which is close to the border with Northern Ireland.
Several shots were fired during the incident at the Lordship Credit Union in the Jenkinstown area at about 9.30pm on Friday.
The officer, who was based at Dundalk Garda station, was fatally injured in the shooting. He was named by Gardai as Detective Garda Adrian Donohoe.
Garda sources said that after shooting the detective the raiders seized the money stolen from the credit union and drove off. Four men who are believed to have fled the scene in a grey Volkswagen Passat are being sought by the force.
Sinn Fein president and Co Louth representative Gerry Adams said he was deeply shocked by the detective's murder. "I extend my deepest sympathies to his family and colleagues, and appeal to those with information about this crime to co-operate with the Gardai," he said.
Jim Loughran, a Sinn Fein councillor in the part of County Louth where the shooting took place, described Donohoe as a quiet family man. "I just spoke to him last week on the street in town. I can't believe this has happened," he said. "This was not just an attack on a Garda detective, it was an attack on the whole community," he said.
The detective is understood to have been married with three children. He lived just over a half a mile from the scene of the attack.
The Lordship Credit Union, where the killing took place, was described as a hub of the small community. It is believed staff were locking up when the incident occurred.
Councillor Declan Breathnach said it was not unusual for it to remain open late . "It would be fairly busy on a Friday evening, with some people just getting their week's pay or wanting to sort out money for the weekend," Breathnach said. "This was just such a despicable, heinous act. I still can't believe it but I utterly condemn it."
Fianna Fail justice spokesman Niall Collins pledged his party's full support to Garda Commissioner Martin Callinan.
Gardai have appealed for witnesses to contact them at Dundalk Garda Station.
Official statistics have shown that crime, apart from burglary, has been falling since the republic's economic downturn started in 2007-2008 although gun crime among gangs, particularly in Dublin, has continued to make headlines.
The death of the Garda officer comes 17 years since the death of a detective who was shot by members of the Provisional IRA while he was taking part in an escort for a cash delivery to a post office in County Limerick.