Israel struck multiple targets in Yemen it said were controlled by Houthis, the last of the Iran-backed groups still fully engaged in the regional war that began 14 months ago.

Israeli forces unleashed a series of strikes on the Yemeni capital, Sanaa, and the western city of Hodeidah on Thursday, killing at least six people and injuring dozens more, the Iran-backed Houthis said in a statement where it vowed to retaliate.

The head of the World Health Organization said he was about to board a flight in the Yemeni capital when the airport came under bombardment.