Italian police say they have arrested an Algerian imam and four Tunisians suspected of planning suicide attacks against Western targets in Iraq.
Italy is often used as a logistical base
The men were seized in a series of raids in Florence and the province of Liguria - which were still ongoing.
The raids were part of an investigation into the Islamic militant group, Ansar al-Islam, police said.
They say Islamic terrorist groups have used Italy as a logistical base, says the BBC's Frances Kennedy in Rome.
The probe began in Genoa two years ago but has spread to the Tuscan capital, Florence.
In the latest raids, police searched a mosque in Florence and a number of homes.
"We have dismantled a cell of Ansar al-Islam," police chief Oscar Fiorolli was quoted as saying. The group is suspected of being behind attacks on coalition targets in Iraq.
A local imam was the alleged ringleader, Italian police said.
In recent years police investigations in Italy have found evidence that Islamic terrorist groups have used the country to get false documents and provide hiding places for members, our Rome correspondent says.
Mosques in various cities have been searched in connection with these inquiries, she says.