A County Derry man has been arrested after more than seven million cigarettes were seized from a lorry trailer stopped near Toome.
The operation, involving the PSNI and Her Majesty's Revenue and Customs (HMRC), happened on Monday August 30.
HMRC have said the find of suspected counterfeit cigarettes was worth an estimated £3m in lost duty and taxes.
The man, who is 28 and from Magherafelt, was later released on bail.
Steve Tracey, assistant director of HMRC's fraud investigation service, said the sale of illegal tobacco costs the UK "around £1.9bn a year".
"This is theft from the taxpayer and undermines legitimate traders," he added.
PSNI Ch Insp Mervyn Seffen explained that the joint operation sends a "powerful message to those engaged in this type of criminality that they will be detained and brought before the courts".
"Those trading in illicit cigarettes can be involved in other organised criminality which brings misery and harm to local communities," he said.
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