Two of the world's largest shipping firms, Maersk and Hapag-Lloyd, said Friday they were suspending passage through a Red Sea strait vital for global commerce, after Yemeni rebel attacks in the area.

The Iran-backed Houthis, who control much of Yemen but are not recognized internationally, say they're targeting shipping to pressure Israel during its two-month-old war with Hamas militants in the Gaza Strip.

The maritime tensions have added to fears that the Gaza conflict could spread.