A devastating blow has struck the heart of American diplomacy in the Middle East.

In a bold and highly coordinated assault, Iran-linked Shia militias have bombed the U.S. Embassy compound in Baghdad, Iraq — the largest and most fortified American diplomatic mission in the world. Powerful explosions rocked the heavily guarded Green Zone late Wednesday, sending massive fireballs into the sky and leaving parts of the sprawling diplomatic headquarters engulfed in flames and thick black smoke.