Muslims should report suspected members of the Islamic State jihadist group to police, as Italians did with leftwing terrorists in the 1970s and 1980s, Florence's imam said on Friday.
"The Muslim community also contains terrorists," Izzedin Elzir told Italian daily Corriere della Sera in an interview.
"We must report them in the way you did with the Red Brigades," said Elzir, who heads Italy's largest Muslim organisation UCOII.
"It is a moral imperative," added Elzir, who is also involved in an Italian project to combat the radicalisation of Muslim prisoners.
Muslims must deny Islamic extremists material, logistical, vocal or moral support, Elzir argued.
Moderate Muslim clerics are working with Italian authorities on a new project aimed at fighting radicalisation in jails, where there are known to be at least 100 extremists, Elzir said.
Under the project, 13 government-approved imams will visit prisoners in jails in Florence, Milan, Turin, Cremona, Verona and Modena , he said.
"We need de-radicalisation projects. These terrorists are a cancer on the face of the earth,"Elzir said.
"Holy War belongs to the time of the Crusades," he added.