Italian anti-terrorist police in Milan are investigating whether six attacks on Muslim targets in northern Italy over the past five months are linked - a concern expressed by the country's main Muslim representatives.
Italian Muslims have condemned a twin bomb attack against a mosque in the northern industrial city of Brescia on Wednesday night.
"With this serious act, we find ourselves facing a worrying escalation in the aggressive strategies against Islamic places of worship in Italy" Hamza Piccardo, secretary general of the Union of Communities and Islamic Organizations in Italy (UCOII) said.
Two explosive devices detonated at 9:45 pm near the main mosque in Brescia which is frequented by the many Muslim immigrants who work in the city.
No injuries were reported.
Earlier this month a petrol bomb was hurled at the car of an imam at a mosque near Milan. No-one was injured in the attack which was denounced by the Muslim community as a hate-crime against followers of their religion.
On Thursday the Internet site Islam-Online.it urged Italian Muslims "not to respond to any provocation" and to "organise the surveillance and to exert pressure on the police so that they guarantee us the safe operation of our centres of aggregation, as well as cultural and religious formation".
Another incident was on 7 August when two petrol bombs were hurled at an Islamic centre in Segrate near Milan. No one was injured in the attack but a car owned by a prayer leader and part of the building housing the centre were damaged.
"We're living in a climate of hate which has been unleashed by continuous claims that mosques are the dens of terrorists", Segrate's chief iman, Ali Abu Shweima said referring to the attack.
The first incident this year involving a Muslim target occurred on 15 April when several petrol bombs were thrown at the Milan office of the British-based Islamic Relief charity.
"Fighting Christian Front?"
It is also the only attack to date for which someone has claimed responsibility with authorities receiving a telephone from a man claiming to represent a previously unknown "Fighting Christian Front".
The man who did not identify himself said that an "Christian tribunal" had "sentenced to death" the centre's director, Paolo Gonzaga. No-one was injured in the attack.
Several weeks before the attack, Gonzaga and his group had organised a series of debates in Milan and in the northern towns of Bologna and Sassuolo in which several foreign based Islamic television preachers were invited to make speeches.
On 3 May petrol bombs were again used in an attack on the offices of an organisation mainly representing Italian converts to Islam, the Italian Islamic religious Community (COREIS) in Milan.
"It is the first serious attack against us. Until then we had never received threats or any sort of intimidation", COREIS deputy president, Yahya Pallavicini, said.
On 10 August two petrol bombs exploded at another Islamic centre this time in Abbiategrasso near Milan. As in the other attacks nobody was injured but the building housing the centre was damaged.
Officials at the centre said a similar attack, previously unreported had taken place on 20 July.
The attacks in 2007 mark a sharp increase compared to previous years. In 2006 the only reported strike against a Muslim target was an act of vandalism on a construction site for a mosque near Siena.
Islamic officials and clerics say the upsurge in attacks has been accompanied by an increase in threats made against Muslims.
"We've handed over to the police all the letters we received full of insults and threats. Most of them were sent to us in the last few months. Some of them contained death threats" Shweima said.
"Not to mention all the vulgar graffiti we are forced to wipe off the walls of our centres every month" he added.