JERUSALEM — Iran fired a barrage of ballistic missiles at Israel on Tuesday evening in a major attack with little advance warning, sending Israelis scrambling for shelter as the security cabinet convened in a bunker and the United States readied forces to come to Israel’s defense.

People reported hearing explosions in Tel Aviv and near Jerusalem, which initiated its alert system, ringing out to tens of thousands of cell phones. The air strikes focused on three Israeli military targets after the deaths of a Hezbollah leader and other high-ranking officials.