Three men have been arrested in Co Armagh after tobacco worth £3 million in lost revenue was seized.
A joint garda and PSNI operation saw eight million cigarettes confiscated.
Officers from HM Revenue and Customs detained three men aged 34, 37 and 55 in Newry on Saturday morning.
Gardai also carried out seven searches of business premises and homes in the Carlingford, Co Louth, area.
Items seized included 100,000 euro (£88,200) in cash, tobacco and equipment used in the manufacture of tobacco products.
One articulated lorry, one rigid lorry, two trailers and one van were seized
Our collaboration, even during a global pandemic, demonstrates that we are committed to working with each other, at every level and in every location to tackle organised crime on a cross- border basisSteve Tracey, HMRC
Mobile fuel-laundering machinery concealed in the articulated lorry was also confiscated.
Steve Tracey, assistant director of the fraud investigation service at HMRC, said: “Multi-agency investigations mounted by the joint agency task force show what can be achieved by our ongoing cross-jurisdictional co-operation to tackle criminality.
“Our collaboration, even during a global pandemic, demonstrates that we are committed to working with each other, at every level and in every location to tackle organised crime on a cross- border basis.”
Irish Justice Minister Charlie Flanagan said it represented a significant success for law enforcement on both sides of the border.
“They demonstrate the close practical co-operation between An Garda Siochana, the Revenue Commissioners and their counterparts in the PSNI and HM Revenue and Customs, and I welcome this successful large-scale co-operation.
“The multi-agency joint agency task force established under the Fresh Start Agreement is making sustained and steady progress in combating cross-border criminal activity.
“We are seeing unprecedented levels of co-operation between law enforcement agencies north and south, in tackling cross-border crime of all types including organised burglary, drug crime, rural and farm crimes as well as smuggling.”