On Tuesday, the Bulgarian government confirmed what the U.S. suspected and Israel had been insisting since last July when a tourist bus near the Black Sea was targeted by suicide bombers: Hezbollah did it. But Israel is also insisting Iran has something to do with the attack, a charge that Iran categorically denies.

Even if Iran was not directly involved in this particular attack, the ties between Hezbollah and Iran are well established, not just politically but financially and militarily. The U.S. estimates that Iran gives Hezbollah between $60 and $100 million every year in financial assistance. Iran has denied, and at other times admitted, to giving Hezbollah weapons -- in an interview on Iranian TV in 2007, Hezbollah’s second-in-command revealed that all Hezbollah suicide bombings and terrorist attacks must be approved by the Iranian ayatollahs.

The Iran mission to the U.S. did not immediately respond to a request for comment.

The attack in Bulgaria killed six people, five Israeli tourists and one Bulgarian.