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.

DUBAI, United Arab Emirates (AP) — In just days, Yemen’s Houthi rebels have begun a new, more violent campaign of attacks targeting ships in the Red Sea, sinking two of them and killing some of their crew.

Greece's Cosmoship Management on Thursday said one person is believed dead and four more have not been seen since Houthi militants attacked the Eternity C cargo ship in the Red Sea this week.

The U.S. military spent hundreds of millions of dollars earlier this year in a six-week barrage intended to stop the Iran-backed Houthi rebels in Yemen from targeting ships in the Red Sea.

Crew members aboard a Liberian-flagged ship set ablaze by a series of attacks in the Red Sea have abandoned the vessel as it took on water.