“Fifteen crew members are missing. The four presumed casualties are among the missing crew members,” the EU’s Operation Aspides naval task force told AFP, citing a private company conducting search and rescue operations.

On Monday, the Iran-backed Houthi rebels attacked the Liberian-flagged bulk carrier Eternity C in the Red Sea off the port city of Hodeida for two days before sinking it.

It was the second such attack on maritime shipping in the vital waterway in as many days after months of hiatus, marking a return to the rebels’ campaign against shipping they accuse of having links to Israel.

The group says it is acting in solidarity with the Palestinian people over the war in Gaza.

“According to our information, the search and rescue operation performed by the private company in the area of the attack is ongoing,” they added.

A total of 25 people were onboard the ship, according to Aspides.

On Wednesday, the Iran-backed Houthis said they had “rescued” an unspecified number of the Eternity C’s crew and taken them to a safe location.

The US embassy for Yemen accused the rebels of kidnapping the survivors.

The Houthis, who control large swathes of the Arabian Peninsula’s poorest country, had paused their attacks a little before a short-lived Gaza ceasefire in January before renewed them in recent days.