A little known group called the Informal Anarchic Federation has claimed responsiblity for the embassy bombings in Rome that come as U.S. cities are already on a heightened state of alert going into the Christmas holiday.
According to the Italian news service ANSA, the claim was found in a small box found next to one of the injured employee workers. There appears to be a link between this morning's bombings and package bombs sent to embassies in Athens in November.
Italian news reports say the claim found today read in Italian, "We have decided to make our voice heard with words and with facts, we will destroy the system of dominance, long live the FAI, long-live Anarchy."
The note appeared to be typed on a computer and was folded a number of times inside a box of mints, according to reports.
Bombs exploded at the Swiss and Chilean embassies, according to police, and a similar suspicious package was sent to the Ukrainian Embassy but proved to contain no explosive material.
According to investigators, the signature on the claim proves the links between the Italian and Greek insurrectionists.
The explosions have put security efforts worldwide on high alert, including New York City, where Police Commissioner Ray Kelly said officials are "on alert" going into the holiday weekend.
"Quite frankly there is always a possibility of an attack here," said Kelly. "We are on the top of the terrorist target list. That is the world in which we live."
"This is not new news for us, the fact that there may be something happening or planned to happen, we have no specific information," he said. "But we are on alert, we are watching indicators we normally watch."
Kelly added that the investigation into the Rome bombings is leaning toward it being a "product of the anarchist community."
Federal authorities will on watch over the coming days, sources tell ABC News, ever-mindful of last Christmas' nightmare with the so-called underwear bomber.
Shoppers searching for last-minute gifts are also likely seeing lots of additional police on public transportation as a precaution.
All embassies and consulates in Rome are being checked for suspicious packages. No explosive material has been detected in mailrooms at the United Kingdom, United States, Israeli, German or French embassies in Rome. But all embassies are intensifying their security.
"We are in the process of reminding all U.S. embassies worldwide to review current mail screening procedures and to continue vigilance when opening mail," a U.S. State Deptartment official told ABC News.
The explosion at the Swiss Embassy badly injured a mailroom employee, sending him to the hospital. The 53-year-old is in danger of losing his left hand, and is being operated on at Policlinico Umberto I Hospital.
''We express total solidarity with the Swiss embassy and all its personnel, who have been subject to a deplorable act of violence that deserves our firmest condemnation,'' said Italian Foreign Minister Franco Frattini, according to The Associated Press.