Hounded by months of deadly Israeli attacks in Syria, Iranian military commanders thought it safe to convene a top-level meeting inside Iran's embassy compound in Damascus, believing it protected by international norms shielding diplomatic missions, according to a dozen Iranian, Syrian and regional officials.

They were wrong.

An airstrike on the compound killed seven Iranian officers on Monday — among them one of Iran's top soldiers, Brig. Gen. Mohammad Reza Zahedi, a senior commander in the Revolutionary Guard (IRGC). It was the boldest, and deadliest, in a series of attacks that have picked off Iranian officials in Syria since December.