PALERMO, ITALY -- A poster bearing mug shots of thuggish-looking men urges passengers arriving at the Sicilian capital's airport to be on the lookout for five of Italy's most-wanted Mafia suspects. Next to one of them, Giuseppe Madonia, someone has scrawled triumphantly: "Captured!"

The arrest 10 days ago of Madonia, held to be the number-two man in the Cupola, the committee that dictates Italian Mafia affairs, marked the opening shot in a campaign of arrests by Italian law enforcers of high-profile organized-crime suspects.

Since Madonia's arrest, nine other alleged mobsters have been caught in Italy and abroad. They include Carmine Alfieri, reputed leader of the Camorra -- the version of the Mafia based in the city of Naples -- and Pasquale, Paolo and Gaspare Cuntrera, brothers who left their native Sicily more than 20 years ago and allegedly rose to become the Mafia's most powerful drug traffickers and money launderers, with contacts and business interests spanning four continents.

The spate of arrests has boosted the battered morale of Italian police and other security forces, stung by their failure to prevent the killings of leading anti-Mafia magistrates Giovanni Falcone and Paolo Borsellino in May and July of this year.

But the roundup of organized crime bosses also has brought warnings of more killings. Analysts say the removal of ruling figures from the Mafia and Camorra will almost certainly provoke fresh clan wars, possibly even more bloody than those in the early 1980s, when more than 500 Sicilian mobsters and their relatives died in a power struggle that saw the so-called Corleone families -- with whom the Madonias have close links -- emerge victorious.

"I think we can expect a lot of bloodshed as the battle rages to fill those vacancies," said a high-ranking police official, who spoke on condition of anonymity. "The arrests could also open up the way for more killings of representatives of the state -- magistrates, policemen or politicians -- as a message that the Mafia is still strong."

The capture of so many mobsters after years of failure is largely attributed to the special powers granted to anti-Mafia fighters after the outcry that followed the slayings of Falcone and Borsellino. Those measures included extra police, the deployment of 7,000 soldiers in Sicily, wider use of telephone tapping and the power to offer lighter sentences and new identities to former mafiosi who turn state's evidence.

In recent weeks, more and more pentiti, or repentant mafiosi, have come forward, encouraged by the government's promise of protection and frightened by the implications of a new clan war, investigators say. It is a process that could prove self-perpetuating, they predict.

"As more of the big names are captured, mobsters who were terrified to speak could now decide to do so," said Elio Romano, police chief of Vicenza, the northern Italian town where Madonia was captured.

Madonia's arrest is the most prestigious victory for the police. The 46-year-old alleged boss had been on the run for nine years before police stopped him in a Mercedes-Benz, his briefcase filled with $45,500 in Italian lire and a pocketbook containing more cash and holy images of the Virgin Mary and Saint Rosalia, the patron saint of Palermo.

Madonia, who was posing as a doctor, is a member of one of the most powerful Mafia families, closely allied to the dominant Corleone gangs and suspected of involvement in numerous killings, including those of Falcone and Borsellino. He has been charged with being a Mafia member, a blanket charge that carries up to a 10-year jail term.

Magistrates were questioning Madonia this week on the Falcone and Borsellino killings. Investigators said that as number-two in the five-member Cupola, Madonia must have had knowledge of the assassinations.

"If it was the Cosa Nostra who ordered the murders, it is almost certain that it was the Cupola which gave those orders," said Achille Serra, the Italian police official who coordinated Madonia's arrest.

For sheer financial clout, however, the arrest of the Cuntrera brothers represents the biggest triumph, observers said. The three were taken into custody on Saturday after Venezuela extradited them. Investigators in Italy said the Cuntreras, who operated from Caracas and have been sought for eight years, acted as heroin and cocaine brokers and money launderers for the Sicilian Mafia and had forged close links with the Gambino family in New York and with the drug barons of Colombia.

The brothers have been charged with Mafia membership and drug trafficking.

Despite the recent successes of police, an estimated 50 organized crime bosses are still at large, investigators said. Three of the five members of the Cupola -- Salvatore "Toto" Riina, Bernardo Provenzano and Benedetto Santapaola -- still live in Sicily, according to former mafiosi who have turned state's evidence.

Riina, generally acknowledged as the most powerful man in the Sicilian Mafia, has been on the run since 1969, when he disappeared from a small town near Bologna where he had been sentenced to exile. The photograph police used on the wanted poster is 25 years old.

Mafia mobsters who have cooperated with police say Riina has had plastic surgery. They claim he still commands the organization from safe houses outside Palermo and that he has been seen in exclusive nightclubs and restaurants in the Sicilian capital. In what was widely seen as a slap in the face for Italian law enforcers, the 62-year-old Mafia boss's lawyer boasted on Italian TV two months ago that he met often with his client in Palermo.