Ten people have been rescued from the Red Sea after their ship sank near Yemen following an attack by the Houthis, according to the European Union’s maritime security mission, with several others believed to be being held by the rebel group.

The death toll from the attack that sank the Liberian-flagged Eternity C ship is the highest from any seaborne assault carried out by the Iranian-backed rebels in the crucial maritime trade route.

A Liberian-flagged cargo ship attacked by Yemen’s Houthi rebels sank Wednesday in the Red Sea. UN Special Envoy of the Secretary-General for Yemen Hans Grundberg said there was “grave concern seeing an escalation in the Red Sea,