The UK and the US have carried out a fresh set of joint airstrikes in Yemen, in the latest bid to stop Houthi attacks.
Defence Secretary Grant Shapps said the latest round of strikes were in "self-defence" and would "deal another blow" to the Iranian-backed militants.
It follows seven rounds of airstrikes on Houthi military sites by the US in recent days and comes after the UK took part in an initial joint strike operation earlier this month against the Houthis.
Since then, ships have continued to be targeted along the vital Red Sea and Gulf of Aden trade routes, with the US military confirming the latest strikes were against eight targets.
Mr Shapps said: "Dangerous Houthi attacks on shipping in the Red Sea have continued to threaten the lives of sailors and disrupt shipping at an intolerable cost to the global economy. Along with our US partners, we have conducted a further round of strikes in self-defence.
"Aimed at degrading Houthi capabilities, this action will deal another blow to their limited stockpiles and ability to threaten global trade. Alongside our ongoing diplomatic efforts, we will continue to support regional stability across the Middle East, working hand in hand with our like-minded partners."
The MoD said that four Royal Air Force Typhoons and a pair of Voyager tankers were involved in the latest military strike, which it said saw multiple targets hit at two military sites near the Sanaa airfield in Yemen.
The department said that a "very rigorous analysis" was carried out to avoid civilian casualties. According to US Central Command, "targets missile systems and launchers, air defence systems, radars and deeply buried weapons storage facilities" were among the targets.
A senior US military official told a press briefing initial assessments indicated missiles, unmanned aerial systems and weapons storage areas had been destroyed which had "degraded their (Houthis') ability to conduct these maritime attacks".
The Houthis' media office in an online statement said that several American and UK raids targeted Yemen's capital, Sanaa.
The second operation between the UK and the US comes after a series of joint military strikes on January 11 which saw US and UK warships and jets hit more than 60 targets in 28 locations.
Rishi Sunak and US President Joe Biden had spoken earlier on Monday evening, with a Number 10 readout stating that the two leaders had agreed "continue efforts alongside international partners to deter and disrupt" attacks by the Houthis.
A joint statement issued by Australia, Bahrain, Canada, the Netherlands, the United Kingdom and the US described the strikes as "proportionate and necessary".
The statement said that the mission targeted Houthi underground storage site as well as locations linked to the Houthis' missile and air surveillance capabilities.
It continued: "The Houthis' now more than 30 attacks on international and commercial vessels since mid-November constitute an international challenge.
"Recognising the broad consensus of the international community, we again acted as part of a coalition of like-minded countries committed to upholding the rules-based order, protecting freedom of navigation and international commerce, and holding the Houthis accountable for their illegal and unjustifiable attacks on mariners and commercial shipping."
The countries also warned: "We will not hesitate to defend lives and the free flow of commerce in one of the world's most critical waterways in the face of continued threats."
While the US, UK and other Western allies have insisted the strikes are not escalatory, it comes as tensions simmer in the Middle East as the Israeli bombardment of Gaza continues.
The Houthis, a Shia rebel group that has held Sanaa since 2014 and been at war with a Saudi-led coalition backing Yemen's exiled government since 2015, have linked their attacks to the Israel-Hamas war.
However, the ships they have targeted increasingly have tenuous links to Israel - or none at all.
The latest operation could raise fresh questions about the need to consult Parliament over military action. It is understood that in contrast to the strikes on January 11, neither Labour leader Sir Keir Starmer nor Commons Speaker Sir Lindsay Hoyle were briefed about the operation.
Mr Sunak, after the first joint mission, gave a statement to MPs at the earliest possible opportunity. It remains to be seen if or when he will come before the Commons after these latest strikes.