Italy has begun an anti-terrorist investigation after a parcel bomb exploded in the hands of EU Commission President Romano Prodi.
Former Italian prime minister Mr Prodi brushed off the incident and urged calm. He was not hurt on Saturday when he opened a letter bomb sent to his home in the central Italian city of Bologna.
"Certainly it's not the best tidings for the next year," a smiling Mr Prodi told journalists in Bologna. "Let's be on our guard, but above all let's not lose our calm."
The parcel bomb, which was planted inside a book and burst into flames when Mr Prodi opened it, was sent less than a week after home-made bombs went off in rubbish bins in the street near his apartment, also without hurting anyone.
Mr Prodi's police escort had been beefed up after the first bombs went off. Police suspect anarchists were behind the attacks but local media said Prodi's escort was put under investigation after the parcel bomb got through them.
The country has been on high alert since a suicide bomber killed 19 Italians last month in a strike against a military police headquarters in southern Iraq.
Opposition leaders accused Prime Minister Silvio Berlusconi of fuelling fears of terror threats after he was quoted as saying the Vatican had been a potential target of an attack with a hijacked airplane.
An interview published in the right-leaning Liberodaily said Mr Berlusconi talked about "a hijacked plane above the Vatican" and "an attack from the sky".
The prime minister's office later released a statement denying he had given an interview to the journalist and had only exchanged Christmas greetings. But Liberostuck by its reporter, and opposition lawmakers condemned Mr Berlusconi for treating the issue lightly.