The US on Wednesday condemned this week's attacks on vessels in the Red Sea, which reignited a crisis that had been dormant since a ceasefire between Washington and the Iran-backed Houthi rebels in April.

An attack by Yemen’s Houthi rebels on a Liberian-flagged cargo ship in the Red Sea killed three mariners and wounded two others, a European Union naval force said Tuesday, highlighting the danger of the group's renewed campaign.

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.