Yemen’s Houthi rebels released footage on Thursday showing their fighters boarded and placed explosives on a Greek-flagged tanker, setting off blasts that put the Red Sea at risk of a major oil spill. The vessel was abandoned earlier, after the Houthis repeatedly attacked it.

In the video, the Iran-backed Houthis chant their motto as the bombs detonated aboard the oil tanker Sounion: “God is the greatest; death to America; death to Israel; curse the Jews; victory to Islam.”

The blasts…