Gardaí have busted an organised crime gang known as the 'Hole in the Roof' group who officers suspect have been behind at least 45 robberies nationwide in the past year.
Detectives targeted the Romanian organised crime gang as part of a massive surveillance operation.
They suspect the group has been terrorising the country for more than five years.
The eastern European group is thought to have netted more than €1m worth of stolen cash and cigarettes and is believed to have been military trained.
Gardaí announced details of yesterday's operation which led to the arrest of four people - three men and one women - during the course of 11 dawn raids in Enniscorthy, Co Wexford.
All the suspects are Romanian nationals - a woman in her 20s and the three men aged in their 30s and 40s.
The four were still being held last night at various stations where they were being questioned under the provisions of anti-gang legislation.
Gardaí believe that the gang members have based themselves in Enniscorthy because of its easy access to Rosslare Europort, which is around half an hour's drive away.
"All the information indicates that they use the port to come in and out - it seems that Enniscorthy was deemed a handy location because if there was any hassle they could just flee the country through the port," a senior source said.
The major organised crime gang has links throughout the European Union and is suspected of a multitude of similar crimes throughout the UK and continental Europe.
More than 50 gardaí, including armed officers from the South Eastern Regional Armed Support Unit and the Garda Drugs and Organised Crime Bureau (DOCB), were involved in the raids, as well as gardaí from Tipperary, Kilkenny, Carlow, Waterford and Wexford.
"The search operation began simultaneously at 6.30am at 11 houses in the Enniscorthy area," a Garda spokesman said.
"During the course of the searches, gardaí seized cash, electronic devices including phones and satellite navigation systems, walkie talkies, car key reader, small quantity of cigarettes, and financial documents.
"Assistance was received from the dog handling unit attached to the Customs at Rosslare Port during the searches."