Yemen's Houthis sank two cargo ships in the Red Sea this week, the first flare-up in seven months in the Iran-backed group's years-long campaign to choke global shipping in protest over the war in Gaza and the plight of the Palestinians.

The cost of insuring commercial ships that sail past Yemen’s Houthi militants surged after the rebels sank two ships and killed sailors this week, underscoring how the attacks have revived risk in the crucial waterway.