The officials hope the arrests will bring them closer to Matteo Messina Denaro, who has been on the run since 1993.

Denaro heads "Cosa Nostra" (Our Thing), which was Italy's most powerful organized criminal group in the 1980s and 90s, but its power has diminished since the start of the new century following mass arrests of its members. The mafia also faces competition from Naples-based Camorra and Calabria's 'Ndrangheta groups.

Fifty-three-year-old Denaro, one of the most wanted criminals in Europe, is known for running an age-old secret message system for the gang using a sheep-based code, "pizzini," in which tiny chits contain messages written in cipher.

Matteo Messina Denaro is also known as the 'Playboy Boss' due to his taste for fast cars, women and gold watches

Gondola, who is in his late 70s, was responsible for alerting the gang members about the new messages placed under a rock at a farm, the police said. "The sheep need shearing… the shears need sharpening" and "the hay is ready" were among the code phrases used to alert the members about the messages.

The police had been trying to track the suspects since 2012.

Italian Prime Minister Matteo Renzi praised the investigators' efforts on his Facebook page: "We have to keep on exactly like this so that we can finally get the fugitive super boss. Italy is united in the fight against organized crime," he wrote.

"The state wins, the mafia loses," Interior Minister Angelino Alfano wrote on Twitter.

shs/jil (AFP, dpa)