A senior Iranian official said Iran's new supreme leader rejected de-escalation offers conveyed by intermediary countries. DUBAI/JERUSALEM, March 17 (Reuters) - Iran’s security chief Ali Larijani was killed by Israel, the government confirmed on Tuesday, the most senior figure targeted since the U.S.-Israeli war’s first day, while a senior Iranian official said Iran’s new supreme leader rejected de-escalation offers conveyed by intermediary countries. Larijani was widely viewed as one of Iran’s