Rescuers have found four more crew members from the ship Eternity C, which Yemen's Houthi rebels sank in the Red Sea.

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.

Germany said its aircraft was in the middle of a routine flight in support of the European Union's counter-Houthi mission.