The Houthis have accused US ally Riyadh of a "dangerous escalation" after it struck military targets belonging to the group on Friday, following the rebels announcing a maritime blockade of the top oil producer and hitting its ships in the Red Sea.

The Iran-aligned Houthis on Monday declared a naval blockade against Saudi Arabia, opening a potential new front against the United States in its war with Iran.

Houthi attacks on Saudi shipping risk adding a new front to the Iran war.