Yemen's Huthis said Sunday US and British air strikes "will not deter us" and vowed a response after dozens of targets were hit in retaliation for the Iran-backed rebels' repeated Red Sea attacks.
The joint air raids in Yemen late Saturday, denounced by Iran, followed a separate wave of unilateral American strikes against Iran-linked targets in Iraq and Syria in response to a drone attack that killed three US soldiers in Jordan.
It was the third time that British and American forces have jointly targeted the Huthis, whose attacks in solidarity with Palestinians in war-battered Gaza have disrupted global trade.
The United States has also carried out a series of air raids against the Yemeni rebels on its own, but their attacks on the vital Red Sea trade route have persisted.
Saturday's strikes hit "36 Huthi targets across 13 locations in Yemen in response to the Huthis' continued attacks against international and commercial shipping as well as naval vessels transiting the Red Sea", the United States, Britain and other countries that provided support for the operation said in a statement.
US Defence Secretary Lloyd Austin said the strikes "are intended to further disrupt and degrade the capabilities of the Iranian-backed Huthi militia to conduct their reckless and destabilising attacks".
Neither Austin nor the joint statement identified the specific places that were hit, but Huthi military spokesman Yahya Saree said the capital Sanaa and other rebel-held areas were targeted.
Saree reported a total of 48 air strikes, and said on social media platform X that "these attacks will not deter us from our... stance in support of the steadfast Palestinian people in the Gaza Strip," where the Israel-Hamas war has raged since early October.
The latest strikes "will not pass without response and punishment", Saree said.
- Meeting 'escalation with escalation' -
Britain's defence ministry said Royal Air Force Typhoon warplanes struck targets including two ground control stations used to operate attack and reconnaissance drones.
Austin said that "coalition forces targeted 13 locations associated with the Huthis' deeply buried weapons storage facilities, missile systems and launchers, air defence systems, and radars".
There were no immediate reports of casualties.
Separately, US Central Command (CENTCOM) said its forces carried out a strike against a Huthi anti-ship missile that "prepared to launch against ships in the Red Sea" early Sunday.
CENTCOM had earlier launched strikes against six other Huthi anti-ship missiles, and on Friday the US military said its forces had shot down eight drones in and near Yemen.
The Huthis began targeting Red Sea shipping in November, saying they were hitting Israel-linked vessels in support of Palestinians in Gaza, ruled by another Iran-backed armed group, Hamas.
US and UK forces responded with strikes against the Huthis, who have since declared American and British interests to be legitimate targets as well.
Huthi spokesman Nasr al-Din Amer said following the Saturday strikes: "We will meet the escalation with escalation."
- 'Unacceptable' -
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.
On January 28, a drone slammed into a base in Jordan, killing three US soldiers and wounding more than 40 -- an attack Washington blamed on Tehran-aligned forces.
US and allied troops in the region have been attacked more than 165 times since mid-October, mostly in Iraq and Syria, but the Jordan deaths were the first from hostile fire during that period.
The United States responded Friday with strikes against dozens of targets at seven Tehran-linked facilities in Iraq and Syria, but did not hit Iranian territory.
Both the Iraqi and Syrian governments condemned the Friday strikes, while Tehran said they would "have no result other than intensifying tension and instability".
Iran also denounced the attacks, with the foreign ministry spokesman saying they "contradict" declared intentions by Washington and London to avoid a "wider conflict" in the Middle East.
Diplomatic sources have said the UN Security Council would convene Monday, after Russia called for a meeting "over the threat to peace and safety created by US strikes on Syria and Iraq".
But British Foreign Secretary David Cameron said Tehran is ultimately responsible for the violence, telling the Sunday Times "we need to send the clearest possible signal to Iran that what they're doing through their proxies is unacceptable".
"You created them, you backed them, you financed them, you provided them with weapons, and you will ultimately be held accountable for what they do," Cameron said.