Yemen's Saudi-backed government forces said Saturday that they had struck Iran-allied Houthi fighters in the Red Sea city of Mocha, as the number of civilians forced to flee the renewed fighting soared.

US news site Axios reported that Saudi Crown Prince Mohammed Bin Salman had twice called US President Donald Trump to request American strikes on the Houthis last week but the request was rejected.

The ongoing clashes follow a week-long Houthi offensive that culminated in the group capturing the remainder of Yemen's Red Sea coast and several strategic islands, and cementing their hold on the Bab al-Mandab Strait at the sea's southern entrance.

The waterway has become an important artery for Saudi Arabian oil exports after Iran largely cut off shipments through the Gulf with its blockade on the Strait of Hormuz at the start of the Middle East war. The Houthis have recently declared their own maritime blockade of Riyadh's Red Sea ports.