Four men have been arrested and more than 11 million cigarettes seized during an HMRC operation in south Armagh last week.
HM Revenue and Customs said the PSNI supported them in the operation last Monday, which saw two premises near Newry searched and 11.5 million non-UK duty paid cigarettes recovered.
Officials also seized a number of vehicles, fuel laundering equipment and 400 litres of illegal fuel.
They said the four men arrested were aged 23, 31, 31 and 33-years-old and, were held on suspicion of evasion of excise duty, evasion of VAT, and money laundering.
They have since been released on bail, with the authorities adding that investigations into the seizure are continuing.
11 Million cigarettes seized in Armagh by HMRC.
Dermot Clarke, operational lead at the HMRC, said: “The trade in illicit cigarettes and tobacco damages funding for essential public services and undermines legitimate traders including small, independent shops that serve local communities.
“We continue to work closely with our partners to relentlessly pursue the determined minority who refuse to play by the rules.”
The PSNI’s district commander for Newry, Mourne and Down, Superintendent Norman Haslett, said: “This is an incredibly significant seizure and shows that we are committed to working with our partners to keep communities safe in Northern Ireland.
“We remain resolute in our efforts to put those suspected of profiting from criminality before the courts.”
According to HMRC, the illicit tobacco and alcohol market collectively costs the UK about £3.3 billion a year.
11 million cigarettes seized in Armagh by HMRC.