Iran launched a barrage of about 200 missiles at Israel that were mostly shot down or missed their targets, escalating a Middle East conflict that now depends on whether and how Israel chooses to retaliate.

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.