“We have followed their entire activities in Australia and Canada, so we have information about financing and their membership in Hezbollah,” Mr. Tsvetanov said at a news conference.

Hezbollah has denied responsibility for the bombing.

The announcement could force the European Union to reconsider designating the Lebanon-based group as a terrorist organization and cracking down on its fund-raising. That would upend Europe’s policy of quiet tolerance of the group, which, in addition to operating schools and social services, is an influential force in Middle East politics, considers Israel an enemy and has extensive links with Iran.

Mr. Tsvetanov did not mention Iran, but the Israeli prime minister, Benjamin Netanyahu, said in a statement on Tuesday, “This is yet a further corroboration of what we have already known, that Hezbollah and its Iranian patrons are orchestrating a worldwide campaign of terror that is spanning countries and continents.”

The United States, too, urged the European Union to condemn Hezbollah. John O. Brennan, President Obama’s chief counterterrorism adviser and his nominee to run the C.I.A., responded in a statement Tuesday: “We call on our European partners as well as other members of the international community to take proactive action to uncover Hezbollah’s infrastructure and disrupt the group’s financing schemes and operational networks in order to prevent future attacks.”

But countries including France and Germany have been wary of taking that step, which could force confrontations with large numbers of Hezbollah supporters living within their borders.