A Saudi-led alliance of Arab states launched an attack on Yemen’s main port city on Wednesday in the largest battle of the Yemen war, aiming to bring the ruling Houthi movement to its knees at the risk of worsening the world’s biggest humanitarian crisis, Reuters reported.

Arab warplanes and warships pounded Houthi fortifications to support ground operations by foreign and Yemeni troops massed south of the port of Hodeidah in operation “Golden Victory”.

Fighting raged near Hodeidah airport and al-Durayhmi, a rural area 10 km (6 miles) south of the city, media controlled by the Arab states and their Yemeni allies reported.

The United Arab Emirates’ state news agency reported that UAE forces and local allies had penetrated the Houthis’ front line on the airport perimeter.

It also reported that four Emirati soldiers had died in Yemen, without specifying whether the deaths were tied to the Hodeidah operation.

So far, the Arab states have not tried to capture such a heavily defended major city since joining the war three years ago against the Iran-aligned Houthis, who control the capital, Sanaa, and most of the populated areas.

The Sunni Muslim Arab states see the Houthi rise as expansionism by their Shi’ite foe Iran.