US forces struck three unmanned vessels and two cruise missiles inside Yemen and an attack drone over the Red Sea on Monday that posed an "imminent threat" to ships in the area, the military said.

Yemen's Iran-backed Huthis have been targeting shipping for months and their attacks have persisted despite repeated US and British strikes aimed at degrading their ability to threaten a vital global trade route.

In Monday's attack, US Central Command (CENTCOM) destroyed "three unmanned surface vessels, two mobile anti-ship cruise missiles, and a one-way attack unmanned aerial vehicle," it said on social media.

"The (vessels) and (missile) weapons were prepared to launch towards... the Red Sea," CENTCOM said, adding that the drone was already airborne.

Those strikes, made between the hours of 4:45 pm and 11:45 pm Sanaa time (1345 GMT to 2045 GMT), were done "in self-defense", it said.

"CENTCOM forces... determined that they presented an imminent threat to merchant vessels and to the US Navy ships in the region."

Over the weekend, US and British forces carried out strikes against 18 Huthi targets across eight locations in Yemen, including weapons storage facilities, attack drones, air defense systems, radars and a helicopter, according to a joint statement.

One person was killed and eight wounded in the attacks, the Huthis' official news agency said late on Sunday.

Co-signed by countries including Australia, Denmark, Bahrain and Canada, the joint statement said that "more than 45 attacks on commercial and naval vessels since mid-November constitute a threat to the global economy, as well as regional security and stability."

The Huthis began attacking Red Sea shipping in November, saying they were hitting Israel-linked vessels in support of Palestinians ravaged by the war in Gaza.

Huthis have declared American and British interests to be legitimate targets as well since those countries began responding militarily to the attacks on shipping.

Anger over Israel's devastating campaign in Gaza -- which began after an unprecedented Hamas attack on October 7 -- has grown across the Middle East, stoking violence involving Iran-backed groups in Lebanon, Iraq, Syria and Yemen.