A joint operation between the PSNI and gardaí has lead to the seizure of eight million cigarettes worth approximately £3 million in lost revenue.
A number of searches took place in Carlingford, Co Louth.
Three men were arrested in Armagh following the seizure.
The operation also included the Revenue Commissioners and HM Revenue and Customs in Northern Ireland.
The items seized were two-and-a half tonnes of raw tobacco, tobacco products manufacturing equipment and mobile fuel-laundering machinery.