UK and US forces have bombed military facilities used by Houthi rebels in Yemen, with Rishi Sunak saying Britain sent a “strong signal” that the militants’ attacks in the Red Sea cannot be carried out with “impunity”.

The air strikes have sparked concerns over a dramatic escalation of tensions in the Middle East.

Experts have warned there is “certainly a risk of wider conflict in the region” and that promised retaliation by the Iran-backed group could push Western powers into engaging beyond targeted and contained strikes.

The Prime Minister insisted the US and UK acted “in self-defence” and that allies would not hesitate to ensure the safety of commercial shipping.

Speaking during a visit to Ukraine, he told broadcasters there has been a significant increase in the number of Houthi attacks on commercial shipping in the Red Sea which put lives at risk, disrupted the global economy and destabilised the region.

We need to send a strong signal that this breach of international law is wrong

“Now it’s clear that that type of behaviour can’t carry on. That’s why we joined with allies in issuing very public condemnation of this behaviour.

“And it’s why I made the decision with allies to take what I believe to be necessary, proportionate and targeted action against military targets to degrade and disrupt Houthi capability. We won’t hesitate to protect lives and ensure the safety of commercial shipping.”

He added: “We need to send a strong signal that this breach of international law is wrong. People can’t act like this with impunity and that’s why together with allies we’ve decided to take this action.”

Asked about fears of regional escalation, the Prime Minister insisted the aim was to “de-escalate tensions and restore stability to the region”, with allies having acted when calls for the Houthis to desist were disregarded.

He said: “We have acted in self-defence. It’s incumbent now on the Houthis to stop carrying out these attacks.”

Mr Sunak is set to make a statement to MPs on Monday about the strikes against the Houthis amid calls for greater consultation in Parliament.

He played down concerns that MPs should have been consulted before the military action, saying he chaired Cobra and Cabinet meetings on Thursday and briefed Sir Keir Starmer and shadow defence secretary John Healey.

Meanwhile, Foreign Secretary Lord Cameron said the strikes sent a message not just to the Houthis, but to Iran as well.

“I think it was proportionate, it was legal, it was absolutely right to do. And I think it sends a very clear message to the Houthis, but also to Iran as well,” he told NBC in an interview.

The UK Government will get assessments of the impact of the action later on Friday, Lord Cameron said.

Labour is “fully supportive” of the action needed to stop Houthi attacks, Sir Keir said.

Asked how concerned he was that MPs will currently not have the opportunity to debate the strikes until Monday, the Labour leader told broadcasters: “I want the Prime Minister to make a statement as soon as possible, but the principle of taking action against the Houthi rebels is really important.”

Shadow foreign secretary David Lammy was in Beirut calling for the cessation of hostilities between Lebanon and Israel and the prevention of the conflict extending further into Lebanon.

Liberal Democrat leader Sir Ed Davey said his party was “minded” to support the Government’s military action, but believed in the “principle” of parliamentary consultation before such intervention is taken.

Commons Speaker Sir Lindsay Hoyle said he was “happy to facilitate” a recall of Parliament “at any time”, but requests by the Government to do so are rare.

Downing Street said that the strikes against the Houthis may not immediately make the Red Sea safer for commercial shipping, but in the “longer term” would have a “positive effect”.

The Government published a summary of its legal position following the strikes, saying military intervention “was lawfully taken” and “this was the only feasible means available to deal with such attacks”.

The strikes on Thursday night were the first to be launched against the militants since they started targeting vessels in the key international trade route, through which some 15% of the world’s shipping passes.

The Ministry of Defence said four Royal Air Force jets struck two Houthi facilities involved in their targeting of HMS Diamond and US Navy vessels on Tuesday.

One was a site at Bani and the other the Abbs airfield, used to launch drones and cruise missiles.

The US Air Force said it struck more than 60 targets at 16 sites in Yemen, including logistical hubs, air defence systems and munitions depots.

The UK and US had non-operational support from Australia, Bahrain, Canada and the Netherlands.

The Houthis on Friday said the US-led operation resulted in at least five deaths and six injuries.

A military spokesperson for the group warned the strikes will not go unpunished and will not deter the militia from supporting Hamas by targeting ships associated with Israel.

Intensified attacks by the Houthis could push Western allies “into areas that they’re not going to feel very comfortable with”, foreign policy expert Sophia Gaston said.

“We are moving into a much riskier terrain because the United States and the United Kingdom certainly do not want to be in a situation where we are required to engage beyond a limited targeted strike capacity and certainly not one that may invite the participation of other regional powers,” she told the PA news agency.

The head of foreign policy at the think tank Policy Exchange also said the existence of so many proxies for different states, such as the Houthis and Hezbollah for Iran, “necessarily makes this a kind of tinderbox”.

“And I think there are a lot of these players who believe that the stakes at the moment are becoming existential.

“So I think that always is a recipe for a higher risk of conflict.”

Dr Tobias Borck, a senior research fellow at the Royal United Services Institute (Rusi) think tank, told PA that the threat of a wider regional war that has existed since Hamas’ deadly October 7 attack on Israel has not changed in light of the strikes.

“However, escalation can happen as a result of accidents and miscalculation, or as a simple compounding of risk, a normalisation of an extremely high level of violence,” he said.

An Iranian professor predicted there will “definitely be escalation” in the region.

Seyed Mohammad Marandi, of the University of Tehran, said that while Iran “doesn’t dictate terms to any of its allies”, it would “support” them in backing the Houthis.