Flag states should order shipping companies to divert vessels from the Red Sea to prevent further seafarer deaths, according to a union.

Houthi rebels have attacked more than 60 merchant ships in the Red Sea this year, killing four seafarers and leaving another seriously wounded from three direct hits, the International Transport Workers’ Federation said.

It said shipping companies and flag states — responsible for safe working environments for crew — must demonstrate their commitment to seafarers by diverting ships away from danger.