The Houthis also attacked shipping in the Red Sea and Gulf of Aden during the Gaza war, saying they were acting in solidarity with the Palestinians, but have so far refrained from doing so in the latest war.

"We affirm that our fingers are on the trigger for direct military intervention," the group said in a statement on Friday, warning that it would act if other nations joined the US-Israeli fight or if the Red Sea was used for "hostile operations".

The Red Sea has become increasingly important during the US-Israeli war with Iran, as Saudi Arabia has diverted a large proportion of its oil exports to the port of Yanbu, with Iran having all but closed the Strait of Hormuz and cut off the Gulf.