Yemen’s Houthi movement says it is ready to “meet escalation with escalation” after US strikes triggered a diplomatic backlash from Moscow and Tehran.

The strikes against the Iran-aligned group over its threat to resume Red Sea shipping attacks have killed at least 31 people.

They mark the biggest US military operation in the Middle East since President Donald Trump took office in January.

The White House posted photos of Trump watching the strikes on Sunday, saying on X the action is to defend US shipping assets and deter terrorist threats.

The Houthis’ political bureau described the attacks as a “war crime”.

“Our Yemeni armed forces are fully prepared to respond to escalation with escalation,” it said on Sunday.

Trump also warned Iran, the Houthis’ main backer, that it needed to end support for the group immediately. He said if Iran threatened the US, “America will hold you fully accountable and, we won’t be nice about it”.

In response, the top commander of Iran’s Revolutionary Guards said the Houthis took their own strategic and operational decisions and Tehran would react decisively to any action against it.

“We warn our enemies that Iran will respond decisively and destructively if they take their threats into action,” Hossein Salami told state media.

Russian Foreign Minister Sergei Lavrov called US Secretary of State Marco Rubio to urge an “immediate cessation of the use of force and the importance for all sides to engage in political dialogue”, Russia’s foreign ministry said on Sunday.

However, Rubio told the CBS News’s Face the Nation on Sunday the strikes would continue until the Houthis no longer had the capability to attack global shipping and the US Navy.

Most of the 31 people confirmed killed in the US strikes were women and children, Anees al-Asbahi, spokesperson for the Houthi-run health ministry said in an updated toll on Sunday.

More than 100 were injured in the neighbourhood known to host members of the Houthi leadership.

Strikes also targeted Houthi military sites in Yemen’s south-western city of Taiz and a power station in the town of Dahyan in Saada, which led to a power cut.

The Houthis, an armed movement that has taken control of most of Yemen over the past decade, said last week they would resume attacks on Israeli ships using Red Sea shipping lanes off Yemen unless Israel lifted a block on aid into Gaza.

The Houthis had launched scores of attacks targeting shipping from November 2023, saying they were in solidarity with Palestinians over Israel’s war with Hamas in Gaza.

The group has launched no new strikes on Red Sea shipping since it halted attacks when Israel and Hamas agreed to a ceasefire in Gaza in January.

US officials, speaking on condition of anonymity, say Trump has authorised a more aggressive approach.

“To all Houthi terrorists, YOUR TIME IS UP, AND YOUR ATTACKS MUST STOP, STARTING TODAY. IF THEY DON’T, HELL WILL RAIN DOWN UPON YOU LIKE NOTHING YOU HAVE EVER SEEN BEFORE!” Trump posted late on Saturday (US time) on his Truth Social platform.

The US military’s Central Command, which oversees troops in the Middle East, described Saturday’s strikes as the start of a large-scale operation across Yemen.

“Houthi attacks on American ships & aircraft (and our troops!) will not be tolerated,” Defence Secretary Pete Hegseth wrote on X.

Iran’s foreign ministry condemned strikes on Yemen as a “gross violation of the principles of the United Nations Charter and the fundamental rules of international law”.

The Lebanese armed group Hezbollah, also backed by Iran, expressed solidarity with the Houthis, calling it “barbaric aggression … and a flagrant violation of international law”.

-with AAP