Four devices in four days were sent from the northern Italian city, to European Commission President Romano Prodi, European Central Bank head Jean-Claude Trichet, EU police agency Europol and Eurojust, which helps fight cross-border crime.
Luigi Persico, assistant prosecutor in Bologna, told reporters on Wednesday the ban would affect all post offices in the Emilia Romagna region around Bologna. Police would be able to intercept any mail addressed to EU bodies or connected groups and check the contents for dangerous substances.
No one has been injured by any of the letter bombs, but the campaign comes at a time of worldwide security jitters after a warning from the United States of an increased threat of terror attacks over the Christmas and New Year festive season.
European police forces continued the hunt on Wednesday for
the Italian anarchists suspected of being behind the mail bombs.
Sources at the prosecutor's office in Bologna said on
Wednesday the packages mailed to Trichet, Europol and
Eurojust contained books and photocopies of a leaflet from the Informal Anarchist Federation.
The leaflet described the Italian group and talked about its
"Operation Santa Claus". The IAF had threatened a campaign against the "new European order" just days before the first device targeted Prodi at his Bologna home on Saturday.