ROME, Aug 15 (AFP) - Italy was on alert on Sunday after a group claiming to be linked to Al-Qaeda threatened to launch attacks throughout the country and target Prime Minister Silvio Berlusconi following the expiry of an ultimatum for Rome to pull its troops out of Iraq.
"This message follows the same logic as the previous ones," Interior Minister Giuseppe Pisanu told a news conference in Rome. "We are not underestimating it but we are not going to be intimidated and we have confidence in the substantial protection measures that have been introduced."
The threat, signed by a group calling itself the Abu Hafs al-Masri Brigades-Al-Qaeda and posted on an Islamist website, did not deter British Prime Minister Tony Blair from arriving in Italy with his family at the weekend to visit Berlusconi.
The Italian and British leaders have been Washington's staunchest allies in the war in Iraq and subsequent occupation.
Pisanu said the government had not received "any particularly worrying information" about a possible attack.
But he warned: "We cannot rule out the possibility of sleeping terrorist groups or some individual acting unannounced on national territory, even without receiving encouragement from abroad."
In the as yet unauthenticated Internet statement, the Abu Hafs al-Masri Brigades-Al-Qaeda said: "Today we declare a bloody war. The earth will shake under the feet of every Italian, God willing."
"We call on all our cells to hit every target they (can) in Italy and to repeat the blows forcefully, until the (Italian) government pulls out of Iraq."
"We declare that Berlusconi is targeted and his head will be the price for the crimes that his (troops) are perpetrating and continue to perpetrate in Iraq."
The statement was the latest in a series purportedly issued by the group since mid-July, threatening to attack Italian targets both in Italy and elsewhere unless Rome withdraws its 3,000-strong force from Iraq by Sunday.
The Italian authorities quietly boosted security in cities, ports, train stations, subways and airports ahead of the deadline on Sunday, which is a major religious and public holiday in Italy.
Hordes of Italians were expected to be on the move during the last big summer holiday weekend, which coincides with Assumption Day, a holy day in the predominantly Roman Catholic country.
Officials have said some 13,000 potential targets are now permanently guarded by 23,000 police and soldiers, between 5,000 and 6,000 of them in Rome. The latter include Fiumicino airport, the Vatican Radio buildings, the US embassy, the Coliseum and the port of Civitavecchia.
Berlusconi's himself has been at his tightly guarded residence on the island of Sardinia for a week.
On Monday, the billionaire media magnate is to receive Blair and his family for a two-day private visit, before the Blairs travel to Tuscany to stay with Prince Strozzi.
The Italian prime minister's Villa Certosa -- a 2,500-square-metre (26,900-square-foot) villa on a 50-hectare (124-acre) estate -- is bigger than the 44-hectare Vatican and is a nightmare to police.
For security reasons the Blairs and their hosts will not be leaving the estate with its six swimming pools and outdoor amphitheatre, and will be under constant surveillance from military helicopters.
Pisanu was due on Sunday to inspect all centres of security operations in Rome.
Hospitals are on alert and and fire chiefs have been ordered to expand their weekend forces in the seven cities seen most at risk -- Florence, Milan, Naples, Palermo, Rome, Turin and Venice.
In its August 15 statement on www.ansarnet.ws, the Abu Hafs al-Masri Brigades-Al-Qaeda said: "The Italian government dug its own grave by following America, the head of infidelity, and remaining in Iraq... Hence it is to blame for all the blood that will be shed in Italy after the expiry of the deadline."
By remaining silent, the Italian people showed that "there is no difference between civilians and military" personnel in Italy and "have also dug their own grave", it said.
The group threatened Italy on July 16 with a bloodbath on the scale of the September 11, 2001, if Berlusconi remained in power.
The organisation has claimed responsibility for the March 11 train bombings in Madrid, which killed 191 people, and for the November 2003 bombings in Istanbul, which killed 25.