PALERMO, Italy, Jan 16 (Reuters) - Italian police said on Monday they had arrested Matteo Messina Denaro, the country's most wanted mafia boss who had been on the run for three decades, swooping on a private hospital in the Sicilian capital Palermo where he had gone for treatment. Prosecutors say Messina Denaro is a boss of Sicily's Cosa Nostra mafia. Italian Prime Minister Giorgia Meloni hailed the arrest as "a great victory for the state that shows it never gives up in the face of the mafia". Messina Denaro, who comes from the small town of Castelvetrano near Trapani, is accused by prosecutors of being solely or jointly responsible for numerous other murders in the 1990s. In 1993 he helped organise the kidnapping of a 12-year-old boy, Giuseppe Di Matteo, in an attempt to dissuade his father from giving evidence against the mafia, prosecutors say.

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