(Photo: AFP)

ROME, Feb. 4 (Xinhua) -- An unusual alliance between two Italian mafia organizations has been brought to light after a large police operation on Tuesday.

Since early morning, police carried out raids in Rome, Naples and at least four other cities across the country, as well as in Spain in cooperation with local law enforcement authorities, the Carabinieri military police said in a statement.

Overall, 33 people were targeted by arrest warrants issued by prosecutors of Rome Anti-Mafia District Directorate (DDA) coordinating the operation.

All of them are believed to be members of two separate drug trafficking rings, both based in the Italian capital and linked to the Calabrian mafia called "Ndrangheta" and Naples' Camorra, respectively.

According to investigators, the two gangs have forged an alliance to provide "mutual support in the specific sector of drug trafficking."

In a later meeting with reporters, judicial authorities did not disclose the names of those arrested but confirmed that their assets -- worth about 1 million euros (1.11 million U.S. dollars) -- were preventively seized.

The two criminal rings targeted in the operation had full control over the drug trafficking in the Italian capital, getting their supplies from Spain, according to the probe.

In a message on Twitter, Mayor of Rome Virginia Raggi welcomed the operation, and thanked prosecutors and Carabinieri forces for their efforts in trying to eradicate the narcotics business in the city.