Gardaí believe they have dismantled a firearms trafficking route operated from Co Louth by an organised crime gang based along the border.
Eighteen firearms and over 900 rounds of ammunition were seized at a premises in Ardee yesterday.
Two men in their 30s have been arrested and are being questioned.
They are being detained under anti-gang legislation and can be questioned for up to seven days.
At around 2pm yesterday, officers from the Garda Drugs and Organised Crime Bureau supported by the Emergency Response Unit raided a business premises on the outskirts of Ardee.
Gardaí had intelligence that the building was being used by a border-based organised crime group involved in firearms trafficking and supplying weapons to other crime gangs.
Six AR-15 assault rifles and 12 semi-automatic 9mm handguns were seized along with over 900 rounds of 9mm and .223 ammunition.
Follow-on searches were subsequently carried out at several other properties in Co Louth.
The Louth Divisional Crime Unit, Louth Drug Units as well as the Garda Dog Unit were also involved.
The arrested men were arrested on suspicion of participation in the activities of a criminal organisation to facilitate firearms trafficking.
Both are being detained at a garda station in Co Louth under Section 50 of the Criminal Justice Act and can be held for up to seven days.
Assistant Commissioner for Organised and Serious Crime Justin Kelly described the seizure as "particularly significant" because he said the guns "would undoubtedly been used to maim, kill and intimidate those in communities across Ireland.
"Weapons such as those seized by gardaí today are the lifeblood of organised criminal groups who often use violence as part of their drug trafficking operations," he said.
"I wish to commend the dedication of all the gardaí involved as operations like today's demonstrate our determination to make Ireland a hostile environment for organised criminal groups to operate."
