Six Moroccan men have been arrested in northern Italy on suspicion of seeking to incite hatred of Pope Benedict among Muslims.
Police in the city of Brescia said the suspects had allegedly banded together to stir up religious hatred.
A note was found calling for the Pope to be punished for converting a Muslim journalist to Roman Catholicism.
According to another source, the suspects are not suspected of planning attacks.
Five of the men, who are all Brescia residents, were placed under house arrest while the sixth was taken into custody.
The note found by police urges Muslim immigrants not to integrate into Italian society, Italian media report.
Police said the six were accused of "setting up a group that aimed to incite discrimination, racial and religious hatred, violence and jihad against Christians and Jews".
The Pope was condemned for converting Egyptian-born Magdi Allam, a former columnist for Italian daily Corriere della Sera.
Mr Allam, an outspoken critic of Muslim militancy and strong supporter of Israel, was baptised by the Pope in March 2008.