Updated

Italian police arrested 45 people Tuesday in an anti-Mafia crackdown in Sicily, including top mobsters who had allegedly been in contact with Bernardo Provenzano, the reputed No. 1 boss apprehended earlier this year.

Investigators said the arrests in Palermo struck at the heart of the Sicilian Mafia, dealing it a serious blow two months after Provenzano was arrested. The investigation, which included almost two years of wiretapping in and around Palermo, gave a clear picture of the crime syndicate in the Sicilian capital, they said.

"We believe that this operation is of extraordinary importance, given the possibility to identify the structure of the Palermo criminal organization and the caliber of the people who have been caught," said Nino De Santis, a top police official in Palermo.

He warned, however, that "this doesn't mean the Palermo Mafia has been dismantled."

CountryWatch: Italy

The operation, code-named "Gotha," involved some 500 policemen, who carried out the arrests in pre-dawn raids. Seven people remained at large and were being sought by police. The suspects have been charged with Mafia association and extortion, officials said.

Some of the suspects had been in touch with Provenzano through his "pizzini," or notes about the administration of Cosa Nostra affairs delivered by Provenzano's lieutenants, investigators said. The notes were written in code to conceal the identities of those he dealt with, and investigators have been working since the arrest to crack the code.

"After the arrest of Provenzano, we saw that the things we heard them discuss were the same as in the 'pizzini' we found in Corleone," said De Santis.

Provenzano was arrested in a farmhouse near Corleone, the Sicilian town that has become synonymous with the Mafia. He had been on the run for more than 40 years.

Among the key suspects arrested Tuesday was Antonino Cina, believed to have been the doctor of previous No. 1 boss Salvatore Riina, who was arrested in 1993. After Riina's capture, Provenzano took over as No. 1 boss.

Also taken into custody was Antonino Rotolo, who was under house arrest but met regularly with his aides and was believed to direct many of Cosa Nostra's activities in Palermo, often in cooperation with Cina.

According to the police, the crackdown also averted a potentially bloody turf war among competing clans seeking to fill a power vacuum after the Provenzano arrest. Conversations among suspects who were wiretapped showed some mobsters had been planning to kill rivals.

"Rotolo seems to be the person that Provenzano counted on the most," said Giuseppe Lumia, a center-left lawmaker and former member of parliament's anti-Mafia commission. The operation showed "how the men closer to Provenzano wanted to eliminate rival families," he added.

The wiretapped conversations "allowed us to put together the current chart of the Palermo Mafia, the relations between the various groups and their top people," said national anti-Mafia Prosecutor Piero Grasso.

The investigation confirmed the Mafia's traditional pyramid structure based on families, said investigators. Among those arrested, 13 were believed to be family chiefs, said Grasso.

In Rome, politicians welcomed the crackdown. Interior Minister Giuliano Amato said "the capture of Provenzano and what is coming out of it give us an advantage for the future."