LISBON, April 6 (Xinhua) -- The suspected leader of a 6.5 million-euro tobacco contraband ring has been arrested, Portugal's National Republican Guard (GNR) announced on Friday.

The Excise Activities Unit (UAF) of the Porto branch of the GNR had been tracking the gang since late 2016.

On Thursday, they swooped on six properties, four of them residential, two commercial in Porto and the surrounding area. This resulted in the arrest of a 44-year-old man, the presumed leader of the gang.

The searches also led to the apprehension of 130,000 cigarettes and 226 kilos of tobacco leaves.

"Most of the tobacco was hidden in false compartments that seemed to have been made especially for the purpose, in a commercial property belonging to the main suspect," a spokesman for the UAF told the Lusa Portuguese News Agency.

Besides the ringleader, a further 10 gang members face charges. They are accused of criminal activity and sophisticated contraband operations in the cities of Porto and Aveiro, in Portugal's north.

Over the course of the investigation, 1,282,000 cigarettes have been confiscated. Five vehicles and two properties have also been seized and 141 bank accounts frozen.

"The estimated value of fraud and tax evasion related to this inquiry, in terms of unpaid customs duty and VAT, tops 6.5 million euros," the spokesman concluded.