Three gardaí responding to a routine call narrowly escaped injury when a masked gunman blasted their patrol car with a shotgun.
The uniformed gardaí had been investigating reports of a stolen car in the Moyross estate in Limerick on Tuesday night when they came under fire.
It's understood they had located the stolen car and were preserving the scene when a masked gunman approached them at Ballygrennan Close, Moyross, and fired two shotgun blasts at their vehicle.
None of the unarmed gardaí was injured, although the rear of their patrol car was riddled with more than a dozen shotgun pellets.
They were said to be "traumatised" following their ordeal.
Six people - three men and three women - were arrested two hours after the shooting in Moyross and were being held for questioning yesterday in the city's Henry Street and Mayorstone Garda stations.
In a follow-up operation yesterday, a shotgun was recovered by gardaí and this was sent for forensic examination to determine whether it was the same weapon used in the shooting.
Gardaí investigating the incident said it marked a new low in their efforts to maintain law and order in Limerick.
"Regrettably, this represents a completely new departure for us as there doesn't appear to any clear motive.
"It was very fortunate that none of our members were injured in this unprovoked attack," said a Garda spokesman.
Gardaí were yesterday carrying out house-to-house inquiries in Moyross, on Limerick's northside, and appealed for witnesses to come forward.
Gardaí don't believe the shooting was connected to Limerick's ongoing feud, although the area is home to several members of one of the feuding factions. Gardaí said they were concentrating their investigation instead on the activities of a "local group".
While many criminal gangs in Limerick city have access to a range of firearms and weaponry, it's understood that the investigation will also examine the possibility of a subversive link to the shooting.
The six people who were arrested following the shooting were being held yesterday under Section 30 of the Offences Against the State Act.
They can be detained for questioning for up to 72 hours. The Garda Representative Association in Limerick has called for the full weight of the law to be imposed on the perpetrators of the attack.
"Any person that would be convicted of this very serious incident in Moyross should be subjected to the full rigours of the law," said the GRA spokesman, Mr Paul Browne.
This marked the second time in the space of a week that shots have been fired at gardaí in the Moyross area.
Last Thursday, shots were also fired at a Garda van on routine patrol in Moyross, although no one was injured.