Yemen's Houthi rebels continued an hourslong attack Tuesday targeting a Liberian-flagged cargo ship in the Red Sea, authorities said, after the group claimed to have sunk another vessel in an assault that threatens to renew combat across the vital waterway.

A Liberian-flagged cargo ship came under fire on Monday in the Red Sea, with two security guards on board reportedly hurt and two others missing in an assault that came after Yemen's Houthi rebels purportedly sunk another vessel in a similar attack.

Two Liberian-flagged ship attacks and a round of Israeli airstrikes early Monday targeting Houthi rebels raised fears of a renewed Houthi campaign against shipping.