Two more letter bombs addressed to senior members of the European Parliament burst into flames and another was intercepted Monday — the seventh since Dec. 27 — leading to a review of security at the European Union (search).

The latest bombings scorched furniture, leaving the letter-openers frightened but unharmed. Investigators suspect an Italian anarchist group — the "Informal Anarchic Federation" (search) — as the likely source for the string of bombs, which have caused no injuries.

"This has to be taken very, very seriously because we don't know whether there is a terrorist background to this or some kind of warning, in whatever form — or whether it is just a bad joke," said Hans-Gert Poettering (search), the head of the conservative faction in the European Parliament who was one of those targeted Monday.

Some questioned why EU personnel were allowed handle the packages in the wake of the earlier bombs.

"That such a device has been able to be delivered to the office of a senior politician is a matter of great concern," said Nelly Maes, a Belgian member of the EU assembly.

In Rome, anti-terrorism officials from around Europe set up a joint task force Monday to look into the spate of letter bombs.

The letters that went off Monday were sent to Poettering's Brussels office as well as the office of British Socialist legislator Gary Titley (search) in Manchester, England.

At Titley's office, a staff member opened a parcel that arrived over the Christmas holidays, and it immediately caught fire, enveloping the office in dense, acrid smoke.

"This was a shocking incident," Titley said. "There can be no justification for these attacks, which in reality are an attack on democracy."

A staffer at Poettering's office opened a padded envelope that appeared to contain a book, and it burst into flames. Poettering was on his way to Brussels from Germany at the time.

Also in Brussels, an identical package was discovered addressed to Jose Ignacio Salafranca (search), a Spanish member of the European People's Party (search). Bomb experts neutralized the explosive.

The two packages found in Brussels were postmarked Dec. 22 from Bologna, the Italian city from which the earlier attacks are believed to have originated. The two packages were "identical in every respect — the same size, posted on the same day and from the same place," said David Harley, a spokesman for European Parliament President Pat Cox.

In Antwerp, near Brussels, police were looking into two other suspicious packages found, although it was unclear whether there was a link with the EU letter bombs.

Beyond the three letter bombs against the EU legislators found Monday, there were no other suspicious packages under review at EU headquarters late Monday, officials said.

European Parliament President Pat Cox said the legislature would intensify security and scanning measures at its vast offices in the heart of Brussels, and told everybody to be on the lookout.

"We are asking members of the European Parliament, together with their families and staff, to be alert in their homes, their offices in the European Parliament and in their constituencies," he said.

Three firefighter trucks and bomb disposal squads were parked outside the Parliament's buildings in central Brussels, and plainclothes policemen were seen moving inside carrying metal boxes.

After the packages were found, parliament staff was told to handle mail with care. Over the Christmas holidays, the EU institution received about 100,000 letters and parcels.

European officials first focused suspicion on the anarchist group after it claimed responsibility for two time bombs that exploded outside European Commission President Romano Prodi's (search) house in Bologna on Dec. 21, causing a small fire.

In a letter to Italian daily newspaper La Repubblica on Dec. 23, the anarchist group said it planted the bombs to "hit at the apparatus of control that is repressive and leading the democratic show that is the new European order."

With Monday's packages, seven letter bombs have targeted senior EU officials in five countries since Dec. 27, when a package exploded in Prodi's home. Explosives were intercepted in the mail to Jean-Claude Trichet, the head of the European Central Bank, in Frankfurt, Germany; and two EU police institutions, Eurojust and Europol, in The Hague, Netherlands.