The US attacked a key Yemen oil port controlled by the Houthis overnight and killed dozens of people, according to the Iran-backed militants, raising the specter of a widening conflict in the Middle East.

The US says the attack on the Red Sea coast aimed to restrict supplies and funds for the Houthis, who called it a war crime.

The death toll from US airstrikes on an oil port in western Yemen has risen to at least 74 people, the Houthi-run health ministry reported, marking the deadliest day since the United States escalated its aerial campaign against the Iran-backed group last month.