The United States and Britain launched a second round of joint military strikes on Yemen's Houthis on Tuesday over their attacks on Red Sea shipping, as the Iran-backed rebels vowed to hit back.
The latest raids, heard by residents of the rebel-held capital Sanaa around midnight (2100 GMT), hit eight Houthi targets, a joint US-UK statement said, while the Houthis listed 18 strikes across their territory.
US and British forces carried out a first wave of strikes against the rebel group earlier this month, and the United States launched further air raids against missiles that Washington said posed imminent threats to both civilian and military vessels.
But the Houthis have vowed to continue their attacks -- just one part of a growing crisis in the Middle East linked to the Israel-Hamas war, which has raised fears of a broader war directly involving Iran.
The latest strikes were against "eight Houthi targets in Yemen in response to the Houthis' continued attacks against international and commercial shipping as well as naval vessels transiting the Red Sea", Washington and London said in a joint statement with other countries that supported the military action.
"These precision strikes are intended to disrupt and degrade the capabilities that the Houthis use to threaten global trade and the lives of innocent mariners," the statement said.
The US Central Command said in a separate statement that the targets of the strikes "included missile systems and launchers, air defence systems, radars, and deeply buried weapons storage facilities".
- Attacks won't go 'unpunished' -
British Foreign Secretary David Cameron said the Houthis had carried out more than 12 attacks on shipping since the first wave of joint strikes on January 11.
"What we have done again is send the clearest possible message that we will continue to degrade their ability to carry out these attacks... (and) that we back our words and our warnings with action," he said in a statement.
The Huthis remained defiant, with military spokesman Yahya Saree promising a response.
"These attacks will not go unanswered and unpunished," he wrote on X, formerly Twitter, listing 18 strikes in Sanaa, Hodeida, Taez and Al-Bayda provinces.
A senior US military official said the strikes were carried out using a combination of precision-guided munitions from US and British aircraft, and Tomahawk cruise missiles.
There were no concerns about civilian casualties at the sites that were hit, while Huthi losses were unknown, the official told journalists.
"The targeting was very specific and... very deliberate to go after the capability that they are using to attack maritime vessels in the Red Sea, Bab al-Mandab and Gulf of Aden," the official added.
Saree did not mention any casualties in his post on X.
Yemen's official Saba news agency said strikes hit Sanaa and several other parts of the country, while Houthi TV outlet Al-Masirah said four strikes targeted the Al-Dailami military base north of the capital, which is under rebel control.