Interior Minister Giuseppe Pisanu said that police were also examining documents seized in raids across Italy.
Pisanu said that 15 people found to be illegally residing in Italy were being expelled from the country, and that one person had been arrested for resisting police.
Pisanu said that those being targeted were "suspected on solid evidence of gravitating toward Islamic extremist fundamentalism."
However, he said that no evidence had emerged from what he termed a "preventive operation."
Italian authorities have carried out large numbers of arrests against Arabs suspected of links to international "terrorism", mainly in the north of the country, only to release most of them later.
"We just want to isolate extremists and violent people so they cannot cause harm," Pisanu said, stressing that lawful Muslims in Italy had the government's full support.