Washington: The US military has fired another wave of missile strikes against Houthi-controlled sites, US Central Command said, marking the fourth time in days it has directly targeted the group in Yemen.

The strikes were launched from ships and submarines in the Red Sea and hit 14 missiles that the command deemed an “imminent threat” after a one-way attack drone was launched from a Houthi-controlled area in Yemen and struck a Marshall Islands-flagged, US-owned and operated ship, the Genco Picardy, in the Gulf of Aden, which the Houthis claimed was a “direct hit”.

“Forces conducted strikes on 14 Iran-backed Houthi missiles that were loaded to be fired in Houthi controlled areas in Yemen,” Central Command said in a statement posted on X late on Thursday afternoon (AEDT).

“These missiles on launch rails presented an imminent threat to merchant vessels and US Navy ships in the region and could have been fired at any time, prompting US forces to exercise their inherent right and obligation to defend themselves.”

Earlier the US announced it had put the Houthis back on its list of specially designated global terrorists. The sanctions that come with the formal designation are meant to sever violent extremist groups from their sources of financing.

But despite the sanctions and military strikes, including a large-scale operation carried out by US and British warships and warplanes that hit more than 60 targets across Yemen late last week, the Houthis are continuing their harassment campaign of commercial and military ships.

The US has also strongly warned Iran to cease providing weapons to the Houthis. Last week, a US raid on a dhow trading vessel intercepted ballistic missile parts the US said Iran was shipping to Yemen. Two US Navy SEALs remain unaccounted for after one was knocked off the vessel by a wave during the seizure and the second followed him into the water.

On Wednesday, Pentagon press secretary Major General Pat Ryder said the US would continue to take military action to prevent further attacks.