More than 27,000 counterfeit and smuggled cigarettes have been seized by Customs officers in raids on businesses in Derry.
Thirty retailers were visited in an operation aimed at the transport, storage and sale of illicit tobacco.
Revenue and Customs officials seized 27,602 cigarettes along with 10kg (22lb) of hand-rolling tobacco.
Officers used scanning equipment which detects covert security markings missing from the fake goods which are contained on legitimate cigarette packets but remain invisible to the naked eye.
Mike Connolly, assistant director in charge of specialist investigations at Customs, said: "The unregulated sale of illegal cigarettes is not a victimless or harmless crime, and encourages otherwise honest people to trade with criminals.
"The gangs behind this form of criminality are motivated solely by greed and personal gain, costing us all, as taxpayers, around £2 billion per year in unpaid duty."