ROME - An Italian man was arrested on Monday for growing cannabis plants in Rome, local media said.

The 57-year-old man grew the dope within an underground tunnel excavated in the 1930s for a subway project in the heart of the Italian capital.

Local police seized around 340 kilos of cannabis reportedly worth about three million euros ($3.6 million).

The man, who claimed to be a regular farmer, produced the drug with high-tech and expensive systems on some seven hectares of hidden plantation.

Police made the discovery as they were surprised by a strong smell of marijuana in the surroundings of the tunnel. The seized cultivation was likely to be part of an international drug ring, they said.