The deadly terrorist attack that took place near the Iranian Embassy in Beirut on Nov. 19 could not have happened at a more sensitive juncture. Taking place a day before the resumption of the talks between Iran and the major powers in Geneva and ahead of a possible signing of an agreement, it also coincided with the visit of French President François Hollande to Israel, which, for its part, scared and alarmed the whole world with its apocalyptic prophecies about the "surrender agreement" with Iran. It occurred while the Middle East was seething and more volatile than it has ever been. It is no wonder that Iran, in an unusual fashion, was quick to point a finger at Israel, holding it accountable for the terrorist act.

Officially, Israel has emphatically denied involvement. The Israeli security officials with whom I spoke sniggered: "Israel has never used suicide bombers. This does not exist in our culture nor do we have any interest in interfering in the war raging between Sunnis and Shiites in the Middle East in general, and in Syria and Lebanon in particular."

The hint of the Israeli officials is all too clear. The attack, according to assessments in Israel, was carried out by a militant terrorist Sunni organization with a highly developed operational infrastructure and top-notch execution capability. The attack itself, experts believe, was complex and hard to carry out. Its results were deadly. According to information available at this point, the Iranian cultural attaché to Lebanon was killed in the blast. A cultural attaché is oftentimes a euphemistic way of referring to a member of the Revolutionary Guard. If this information was correct, the perpetrators accomplished their objective.

The story is both complex and simple. An all-out war is taking place between the Shiites and Sunnis in the Middle East, with Syria being the main and exposed battlefield. Hezbollah has sided — openly and in large numbers — with Syrian President Bashar al-Assad against the Sunnis. Now the Sunnis have come to Beirut, to the backyard of Sheikh Hassan Nasrallah, the organization's secretary-general, to tell him with a stentorian voice: You cannot avoid your accountability. You're in way too deep. Anyone serving Iran on Syrian soil will find Iran's enemies in his own back yard, in Beirut.