Update: 1 p.m. ET
ROME -- The ANSA news agency says a flyer of the Informal Anarchist Federation was found inside the package.
The group claimed responsibility for a thwarted attack against the chief executive of Deutsche Bank this week and warned in that claim that there would be two more "explosions."
Update: 10 a.m. ET
ROME - A letter bomb exploded Friday at an office of Italy's tax collection agency, slightly wounding the organization's director. Police were probing possible links to an Italian anarchist group that claimed credit for a thwarted attack against the chief executive of Deutsche Bank this week and warned there would be two more "explosions."
A Rome police official, who spoke on customary condition of anonymity, said the bomb was in a yellow bubble envelope mailed to the director's attention at an Equitalia office on the outskirts of Rome. He said there was no direct evidence yet linking Friday's bomb to the one Wednesday in Frankfurt, Germany, but that police were on high alert.
The Italian group, known as the "Informal Anarchist Federation" claimed responsibility for package bombs sent to three Rome embassies around Christmas last year.
The tax agency director, identified by the government as Marco Cuccagna, suffered a light hand injury. His eyes were not injured, contrary to an earlier report. He was taken to a hospital for treatment, Police Chief Francesco Tagliente told The Associated Press.
"We are working to try to understand the dynamic of what happened," Tagliente said at the scene. "The director opened an envelope that exploded, and he was injured on his hand."
Premier Mario Monti, who is pushing a package of tax hikes and spending cuts to help Italy solve a financial crisis, issued a statement expressing solidarity with Cuccagna.
"Equitalia has always done, and continues to do, its duty in full compliance with the law. It performs an essential role for the functioning of the state, without which it would be possible to provide services to citizens and their families," said Monti, who is in Brussels for a European Union summit.
'Banks, bankers, ticks and bloodsuckers'
On Wednesday in Frankfurt, a routine mailroom screening found a bomb contained in a small package that was addressed to Deutsche Bank CEO Josef Ackermann. The explosive was deactivated without incident.
Tucked alongside that bomb was a letter of responsibility from the anarchist group.
The letter, written in Italian, promised "three explosions against banks, bankers, ticks and bloodsuckers," according to the Hesse state Criminal Office. Authorities said Thursday that they were worried that two bombs remained undetected.
On Dec. 23, 2010, identical package bombs exploded at the Swiss and Chilean embassies in Rome, badly wounding the two people who opened them. A third bomb was safely defused at the Greek Embassy four days later.
The anarchist group, known by the acronym FAI, claimed responsibility for the embassy bombs, saying it was acting in solidarity with jailed Greek anarchists who had asked their comrades to organize and coordinate a global "revolutionary war."
Extreme left-wing and anarchist movements have existed for decades in Europe. They staged deadly attacks across the continent in the 1960s and 1970s.
Though more sporadic in recent decades, official figures show attacks linked to such groups are on the rise, with most of the incidents in Italy, Spain and Greece.
Greece, Spain and to a lesser extent Italy have been hit hard by government cutbacks and unemployment resulting from a continent-wide debt crisis.
The Associated Press and Reuters contributed to this report.