The three, detained at the request of the Moroccan authorities, are also accused of fundraising to finance subversive activities, police claimed.
"The operation took place last night (Saturday) in a number of Italian cities," a spokesman for the Varese police, near Milan said.
Police in the central city of Florence said Muhammad Rafiq, who used to be a cleric at a mosque in the city outskirts, had previously been investigated as part of an inquiry following the 11 September, 2001 attacks on the United States.
He was a Muslim cleric in Cremona, northern Italy. There were no police records of the other two arrested men.
Bin Laden tapes
The arrests coincided with fresh threats purportedly made by Usama bin Ladin against the US and its western and Muslim allies.
In tapes aired on Saturday by Aljazeera television, bin Ladin vowed to “continue to conduct martyrdom operations inside and outside the United States”. He warned that all countries that backed Washington over Iraq were targets.
In June this year, Italy’s financial police arrested six people they claimed had close links with al-Qaida group.
More than 170 policemen searched 40 houses in a major sweep in the north around Milan.
The raid was “part of a massive operation against international terrorism coordinated with the Milan prosecutor, Luigi Orsi”, a statement said.
Those arrested included five Tunisians and a Moroccan.